diff --git a/account_reconciliation_widget_due_date/README.rst b/account_reconciliation_widget_due_date/README.rst
index 3ee0acaf..df6c6627 100644
--- a/account_reconciliation_widget_due_date/README.rst
+++ b/account_reconciliation_widget_due_date/README.rst
@@ -66,6 +66,7 @@ Contributors
 * `Tecnativa <https://www.tecnativa.com>`__:
 
   * Víctor Martínez
+  * Alexandre D. Díaz
 
 Maintainers
 ~~~~~~~~~~~
diff --git a/account_reconciliation_widget_due_date/i18n/account_reconciliation_widget_due_date.pot b/account_reconciliation_widget_due_date/i18n/account_reconciliation_widget_due_date.pot
index 271bfc8f..c0f43d9b 100644
--- a/account_reconciliation_widget_due_date/i18n/account_reconciliation_widget_due_date.pot
+++ b/account_reconciliation_widget_due_date/i18n/account_reconciliation_widget_due_date.pot
@@ -6,8 +6,6 @@ msgid ""
 msgstr ""
 "Project-Id-Version: Odoo Server 13.0\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2021-05-31 07:14+0000\n"
-"PO-Revision-Date: 2021-05-31 07:14+0000\n"
 "Last-Translator: \n"
 "Language-Team: \n"
 "MIME-Version: 1.0\n"
@@ -30,13 +28,6 @@ msgstr ""
 msgid "Due date"
 msgstr ""
 
-#. module: account_reconciliation_widget_due_date
-#. openerp-web
-#: code:addons/account_reconciliation_widget_due_date/static/src/js/reconciliation_model.js:0
-#, python-format
-msgid "Open balance"
-msgstr ""
-
 #. module: account_reconciliation_widget_due_date
 #. openerp-web
 #: code:addons/account_reconciliation_widget_due_date/static/src/js/reconciliation_renderer.js:0
diff --git a/account_reconciliation_widget_due_date/models/reconciliation_widget.py b/account_reconciliation_widget_due_date/models/reconciliation_widget.py
index 818a815f..4af09244 100644
--- a/account_reconciliation_widget_due_date/models/reconciliation_widget.py
+++ b/account_reconciliation_widget_due_date/models/reconciliation_widget.py
@@ -1,4 +1,5 @@
 # Copyright 2021 Tecnativa - Víctor Martínez
+# Copyright 2021 Tecnativa - Alexandre D. Díaz
 # License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl.html).
 
 from odoo import api, models
@@ -15,16 +16,12 @@ class AccountReconciliation(models.AbstractModel):
         return data
 
     @api.model
-    def process_bank_statement_line(self, st_line_ids, data):
-        res = super().process_bank_statement_line(st_line_ids, data)
-        AccountMove = self.env["account.move"]
-        st_line_Move = self.env["account.bank.statement.line"]
-        key = 0
-        for move in res["moves"]:
-            if "date_due" in data[key] and data[key]["date_due"]:
-                move_record = AccountMove.browse(move)
-                st_line = st_line_Move.browse(st_line_ids[key])
-                st_line.date_due = parse_date(self.env, data[key]["date_due"])
-                move_record.line_ids.date_maturity = st_line.date_due
-            key += 1
-        return res
+    def update_bank_statement_line_due_date(self, move_ids, st_line_ids, dates):
+        """'move_ids', 'st_line_ids' and 'dates' must have the same length"""
+        account_move_obj = self.env["account.move"]
+        st_line_move_obj = self.env["account.bank.statement.line"]
+        for index, move_id in enumerate(move_ids):
+            move_record = account_move_obj.browse(move_id)
+            st_line = st_line_move_obj.browse(st_line_ids[index])
+            st_line.date_due = parse_date(self.env, dates[index])
+            move_record.line_ids.date_maturity = st_line.date_due
diff --git a/account_reconciliation_widget_due_date/readme/CONTRIBUTORS.rst b/account_reconciliation_widget_due_date/readme/CONTRIBUTORS.rst
index ae3b3ea5..38eff7f7 100644
--- a/account_reconciliation_widget_due_date/readme/CONTRIBUTORS.rst
+++ b/account_reconciliation_widget_due_date/readme/CONTRIBUTORS.rst
@@ -1,3 +1,4 @@
 * `Tecnativa <https://www.tecnativa.com>`__:
 
   * Víctor Martínez
+  * Alexandre D. Díaz
diff --git a/account_reconciliation_widget_due_date/static/description/index.html b/account_reconciliation_widget_due_date/static/description/index.html
index f8bfcb63..21955d0d 100644
--- a/account_reconciliation_widget_due_date/static/description/index.html
+++ b/account_reconciliation_widget_due_date/static/description/index.html
@@ -3,7 +3,7 @@
 <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
 <head>
 <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
-<meta name="generator" content="Docutils: http://docutils.sourceforge.net/" />
+<meta name="generator" content="Docutils 0.15.1: http://docutils.sourceforge.net/" />
 <title>Account Reconciliation Widget Due Date</title>
 <style type="text/css">
 
@@ -414,6 +414,7 @@ If you spotted it first, help us smashing it by providing a detailed and welcome
 <ul class="simple">
 <li><a class="reference external" href="https://www.tecnativa.com">Tecnativa</a>:<ul>
 <li>Víctor Martínez</li>
+<li>Alexandre D. Díaz</li>
 </ul>
 </li>
 </ul>
diff --git a/account_reconciliation_widget_due_date/static/src/js/reconciliation_action.js b/account_reconciliation_widget_due_date/static/src/js/reconciliation_action.js
index e1b91c14..f0d34a6e 100644
--- a/account_reconciliation_widget_due_date/static/src/js/reconciliation_action.js
+++ b/account_reconciliation_widget_due_date/static/src/js/reconciliation_action.js
@@ -1,13 +1,17 @@
+/* Copyright 2021 Tecnativa - Víctor Martínez
+ * License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl). */
+
 odoo.define(
     "account_reconciliation_widget_due_date.ReconciliationClientAction",
     function(require) {
         "use strict";
-        var action = require("account.ReconciliationClientAction");
 
-        action.StatementAction.include({
+        const ReconciliationClientAction = require("account.ReconciliationClientAction");
+
+        ReconciliationClientAction.StatementAction.include({
             custom_events: _.extend(
                 {},
-                action.StatementAction.prototype.custom_events,
+                ReconciliationClientAction.StatementAction.prototype.custom_events,
                 {
                     change_date_due: "_onAction",
                 }
diff --git a/account_reconciliation_widget_due_date/static/src/js/reconciliation_model.js b/account_reconciliation_widget_due_date/static/src/js/reconciliation_model.js
index 1c6be636..a654f1a5 100644
--- a/account_reconciliation_widget_due_date/static/src/js/reconciliation_model.js
+++ b/account_reconciliation_widget_due_date/static/src/js/reconciliation_model.js
@@ -1,154 +1,86 @@
-/* eslint-disable init-declarations */
-/* eslint-disable-line no-shadow */
+/* Copyright 2021 Tecnativa - Víctor Martínez
+ * Copyright 2021 Tecnativa - Alexandre D. Díaz
+ * License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl). */
+
 odoo.define("account_reconciliation_widget_due_date.ReconciliationModel", function(
     require
 ) {
     "use strict";
 
-    var Model = require("account.ReconciliationModel");
-    var utils = require("web.utils");
-    var session = require("web.session");
-    var core = require("web.core");
-    var _t = core._t;
-    Model.StatementModel.include({
+    const ReconciliationModel = require("account.ReconciliationModel");
+
+    ReconciliationModel.StatementModel.include({
+        /**
+         * @param {String} handle
+         * @param {Moment} date_due
+         * @param {Boolean} preserveMode
+         * @returns {Promise}
+         */
         changeDateDue: function(handle, date_due, preserveMode) {
-            var self = this;
-            var line = this.getLine(handle);
+            const line = this.getLine(handle);
             line.st_line.date_due = date_due;
-            return Promise.resolve(date_due)
-                .then(function() {
-                    return self._computeLine(line);
-                })
-                .then(function() {
-                    return self.changeMode(
-                        handle,
-                        preserveMode ? line.mode : "default",
-                        true
-                    );
-                });
+
+            return this._computeLine(line)
+                .then(() =>
+                    this.changeMode(handle, preserveMode ? line.mode : "default", true)
+                )
+                .then(() => date_due);
         },
+
+        /**
+         * @override
+         */
+        _validatePostProcess: function(data) {
+            if (_.isEmpty(this._validateLineHandles)) {
+                return this._super.apply(this, arguments);
+            }
+            const line_ids = [];
+            const dates = [];
+            for (const handle of this._validateLineHandles) {
+                const line = this.getLine(handle);
+                line_ids.push(line.id);
+                dates.push(line.st_line.date_due);
+            }
+
+            const tasks = [];
+            tasks.push(this._super.apply(this, arguments));
+            tasks.push(
+                this._rpc({
+                    model: "account.reconciliation.widget",
+                    method: "update_bank_statement_line_due_date",
+                    args: [data.moves, line_ids, dates],
+                    context: this.context,
+                })
+            );
+            return Promise.all(tasks);
+        },
+
+        /**
+         * @override
+         */
         validate: function(handle) {
-            var self = this;
-            this.display_context = "validate";
-            var handles = [];
+            // TODO: Check if need recalculate this is next versions
+            let line_handles = [];
             if (handle) {
-                handles = [handle];
+                line_handles = [handle];
             } else {
-                _.each(this.lines, function(line, handle) {
+                _.each(this.lines, (line, line_handle) => {
                     if (
                         !line.reconciled &&
                         line.balance &&
                         !line.balance.amount &&
                         line.reconciliation_proposition.length
                     ) {
-                        handles.push(handle);
+                        line_handles.push(line_handle);
                     }
                 });
             }
-            var ids = [];
-            var values = [];
-            var handlesPromises = [];
-            _.each(handles, function(handle) {
-                var line = self.getLine(handle);
-                var props = _.filter(line.reconciliation_proposition, function(prop) {
-                    return !prop.invalid;
-                });
-                var computeLinePromise;
-                if (props.length === 0) {
-                    // Usability: if user has not chosen any lines and click validate, it has the same behavior
-                    // as creating a write-off of the same amount.
-                    props.push(
-                        self._formatQuickCreate(line, {
-                            account_id: [
-                                line.st_line.open_balance_account_id,
-                                self.accounts[line.st_line.open_balance_account_id],
-                            ],
-                        })
-                    );
-                    // Update balance of line otherwise it won't be to zero and another line will be added
-                    line.reconciliation_proposition.push(props[0]);
-                    computeLinePromise = self._computeLine(line);
-                }
-                ids.push(line.id);
-                handlesPromises.push(
-                    Promise.resolve(computeLinePromise).then(function() {
-                        var values_dict = {
-                            partner_id: line.st_line.partner_id,
-                            counterpart_aml_dicts: _.map(
-                                _.filter(props, function(prop) {
-                                    return !isNaN(prop.id) && !prop.already_paid;
-                                }),
-                                self._formatToProcessReconciliation.bind(self, line)
-                            ),
-                            payment_aml_ids: _.pluck(
-                                _.filter(props, function(prop) {
-                                    return !isNaN(prop.id) && prop.already_paid;
-                                }),
-                                "id"
-                            ),
-                            new_aml_dicts: _.map(
-                                _.filter(props, function(prop) {
-                                    return isNaN(prop.id) && prop.display;
-                                }),
-                                self._formatToProcessReconciliation.bind(self, line)
-                            ),
-                            to_check: line.to_check,
-                            date_due: line.st_line.date_due,
-                        };
 
-                        // If the lines are not fully balanced, create an unreconciled amount.
-                        // line.st_line.currency_id is never false here because its equivalent to
-                        // statement_line.currency_id or statement_line.journal_id.currency_id or statement_line.journal_id.company_id.currency_id (Python-side).
-                        // see: get_statement_line_for_reconciliation_widget method in account/models/account_bank_statement.py for more details
-                        var currency = session.get_currency(line.st_line.currency_id);
-                        var balance = line.balance.amount;
-                        if (!utils.float_is_zero(balance, currency.digits[1])) {
-                            var unreconciled_amount_dict = {
-                                account_id: line.st_line.open_balance_account_id,
-                                credit: balance > 0 ? balance : 0,
-                                debit: balance < 0 ? -balance : 0,
-                                name: line.st_line.name + " : " + _t("Open balance"),
-                            };
-                            values_dict.new_aml_dicts.push(unreconciled_amount_dict);
-                        }
-                        values.push(values_dict);
-                        line.reconciled = true;
-                    })
-                );
-
-                _.each(self.lines, function(other_line) {
-                    if (other_line != line) {
-                        var filtered_prop = other_line.reconciliation_proposition.filter(
-                            p =>
-                                !line.reconciliation_proposition
-                                    .map(l => l.id)
-                                    .includes(p.id)
-                        );
-                        if (
-                            filtered_prop.length !=
-                            other_line.reconciliation_proposition.length
-                        ) {
-                            other_line.need_update = true;
-                            other_line.reconciliation_proposition = filtered_prop;
-                        }
-                        self._computeLine(line);
-                    }
-                });
-            });
-
-            return Promise.all(handlesPromises).then(function() {
-                return self
-                    ._rpc({
-                        model: "account.reconciliation.widget",
-                        method: "process_bank_statement_line",
-                        args: [ids, values],
-                        context: self.context,
-                    })
-                    .then(self._validatePostProcess.bind(self))
-                    .then(function() {
-                        self.valuenow += handles.length;
-                        return {handles: handles};
-                    });
+            // HACK: Store handles to use it in '_validatePostProcess' and frees at promise resolution
+            this._validateLineHandles = line_handles;
+            return this._super.apply(this, arguments).then(results => {
+                this._validateLineHandles = null;
+                return results;
             });
         },
     });
diff --git a/account_reconciliation_widget_due_date/static/src/js/reconciliation_renderer.js b/account_reconciliation_widget_due_date/static/src/js/reconciliation_renderer.js
index c29c1eff..4ae8b18e 100644
--- a/account_reconciliation_widget_due_date/static/src/js/reconciliation_renderer.js
+++ b/account_reconciliation_widget_due_date/static/src/js/reconciliation_renderer.js
@@ -1,52 +1,70 @@
+/* Copyright 2021 Tecnativa - Víctor Martínez
+ * Copyright 2021 Tecnativa - Alexandre D. Díaz
+ * License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl). */
+
 odoo.define("account_reconciliation_widget_due_date.ReconciliationRenderer", function(
     require
 ) {
     "use strict";
 
-    var renderer = require("account.ReconciliationRenderer");
-    var basic_fields = require("web.basic_fields");
-    var core = require("web.core");
-    var _t = core._t;
+    const ReconciliationRenderer = require("account.ReconciliationRenderer");
+    const basic_fields = require("web.basic_fields");
+    const core = require("web.core");
 
-    renderer.LineRenderer.include({
+    const _t = core._t;
+
+    ReconciliationRenderer.LineRenderer.include({
+        /**
+         * @override
+         */
         _onFieldChanged: function(event) {
-            var fieldName = event.target.name;
+            const fieldName = event.target.name;
             if (fieldName === "date_due") {
-                var date_due = event.data.changes.date_due;
+                const date_due = event.data.changes.date_due;
                 this.trigger_up("change_date_due", {data: date_due});
             } else {
                 this._super.apply(this, arguments);
             }
         },
+
+        /**
+         * @override
+         */
         start: function() {
-            this._super.apply(this, arguments);
-            var self = this;
-            this._makeDateDueRecord().then(function(recordID) {
-                self.fields.date_due = new basic_fields.FieldDate(
-                    self,
-                    "date_due",
-                    self.model.get(recordID),
-                    {
-                        mode: "edit",
-                        attrs: {placeholder: _t("Select Due date")},
-                    }
-                );
-                if (self._initialState.st_line.date_due !== "") {
-                    self.fields.date_due.value = self._initialState.st_line.date_due;
-                }
-                self.fields.date_due.insertAfter(
-                    self.$(".accounting_view caption .o_buttons")
-                );
-            });
+            return Promise.all([
+                this._super.apply(this, arguments),
+                this._makeDateDueRecord(),
+            ]);
         },
+
+        /**
+         *
+         * @returns {Promise}
+         */
         _makeDateDueRecord: function() {
-            var field = {
+            const field = {
                 type: "date",
                 name: "date_due",
             };
-            return this.model.makeRecord("account.bank.statement.line", [field], {
-                date_due: {},
-            });
+            return this.model
+                .makeRecord("account.bank.statement.line", [field], {
+                    date_due: {},
+                })
+                .then(recordID => {
+                    this.fields.date_due = new basic_fields.FieldDate(
+                        this,
+                        "date_due",
+                        this.model.get(recordID),
+                        {
+                            mode: "edit",
+                            attrs: {placeholder: _t("Select Due date")},
+                        }
+                    );
+                    if (this._initialState.st_line.date_due !== "") {
+                        this.fields.date_due.value = this._initialState.st_line.date_due;
+                    }
+                    this.fields.date_due.appendTo(this.$(".accounting_view caption"));
+                });
         },
     });
 });
diff --git a/account_reconciliation_widget_due_date/tests/test_account_reconciliation_widget_date_due.py b/account_reconciliation_widget_due_date/tests/test_account_reconciliation_widget_date_due.py
index a247900a..b80cfe1f 100644
--- a/account_reconciliation_widget_due_date/tests/test_account_reconciliation_widget_date_due.py
+++ b/account_reconciliation_widget_due_date/tests/test_account_reconciliation_widget_date_due.py
@@ -95,13 +95,10 @@ class TestAccountReconciliationWidgetDueDate(TransactionCase):
         ]
         res = reconciliation_widget.process_bank_statement_line(
             [line_b.id],
-            [
-                {
-                    "partner_id": line_b.partner_id.id,
-                    "new_aml_dicts": new_aml_dicts,
-                    "date_due": line_b.date_due,
-                }
-            ],
+            [{"partner_id": line_b.partner_id.id, "new_aml_dicts": new_aml_dicts}],
+        )
+        reconciliation_widget.update_bank_statement_line_due_date(
+            res["moves"], [line_b.id], [line_b.date_due],
         )
         self.assertEqual(len(res["moves"]), 1)
         move = account_move_model.browse(res["moves"][0])
@@ -123,13 +120,10 @@ class TestAccountReconciliationWidgetDueDate(TransactionCase):
         ]
         res = reconciliation_widget.process_bank_statement_line(
             [line_c.id],
-            [
-                {
-                    "partner_id": line_c.partner_id.id,
-                    "new_aml_dicts": new_aml_dicts,
-                    "date_due": "2021-02-05",
-                }
-            ],
+            [{"partner_id": line_c.partner_id.id, "new_aml_dicts": new_aml_dicts}],
+        )
+        reconciliation_widget.update_bank_statement_line_due_date(
+            res["moves"], [line_c.id], ["2021-02-05"],
         )
         self.assertEqual(line_c.date_due, date(2021, 2, 5))
         self.assertEqual(len(res["moves"]), 1)