diff --git a/l10n_us_hr_payroll/data/state/mo_missouri.xml b/l10n_us_hr_payroll/data/state/mo_missouri.xml
index 230e24eb..73ea5109 100644
--- a/l10n_us_hr_payroll/data/state/mo_missouri.xml
+++ b/l10n_us_hr_payroll/data/state/mo_missouri.xml
@@ -44,6 +44,7 @@
         <field name="country_id" ref="base.us"/>
     </record>
     <data noupdate="1">
+        <!-- https://dor.mo.gov/forms/4282_2019.pdf -->
         <record id="rule_parameter_us_mo_sit_rate_2019" model="hr.rule.parameter.value">
             <field name="parameter_value">[
                 (1053.0, 1.5),
@@ -59,6 +60,8 @@
             <field name="rule_parameter_id" ref="rule_parameter_us_mo_sit_rate"/>
             <field name="date_from" eval="datetime(2019, 1, 1).date()"/>
         </record>
+        <!-- https://dor.mo.gov/forms/4282_2020.pdf -->
+        <!-- Income Tax Withholding Percentage Table-->
         <record id="rule_parameter_us_mo_sit_rate_2020" model="hr.rule.parameter.value">
             <field name="parameter_value">[
                 (1073.0, 1.5),
@@ -82,6 +85,7 @@
         <field name="country_id" ref="base.us"/>
     </record>
     <data noupdate="1">
+        <!-- https://dor.mo.gov/forms/4282_2019.pdf -->
         <record id="rule_parameter_us_mo_sit_deduction_2019" model="hr.rule.parameter.value">
             <field name="parameter_value">{
                 'single':             12400.0,
@@ -91,6 +95,8 @@
             <field name="rule_parameter_id" ref="rule_parameter_us_mo_sit_deduction"/>
             <field name="date_from" eval="datetime(2019, 1, 1).date()"/>
         </record>
+        <!-- https://dor.mo.gov/forms/4282_2020.pdf -->
+        <!-- 2020 Missouri Withholding Tax Formula Page.12 -->
         <record id="rule_parameter_us_mo_sit_deduction_2020" model="hr.rule.parameter.value">
             <field name="parameter_value">{
                 'single':             12400.0,
diff --git a/l10n_us_hr_payroll/tests/test_us_mo_missouri_payslip_2020.py b/l10n_us_hr_payroll/tests/test_us_mo_missouri_payslip_2020.py
index 164b0f0f..ff6a0ca1 100755
--- a/l10n_us_hr_payroll/tests/test_us_mo_missouri_payslip_2020.py
+++ b/l10n_us_hr_payroll/tests/test_us_mo_missouri_payslip_2020.py
@@ -1,5 +1,6 @@
+# Part of Hibou Suite Professional. See LICENSE_PROFESSIONAL file for full copyright and licensing details.
 
-from datetime import date
+from datetime import date, timedelta
 from .common import TestUsPayslip
 
 
@@ -8,98 +9,26 @@ class TestUsMoPayslip(TestUsPayslip):
     MO_UNEMP_MAX_WAGE = 11500.0
     MO_UNEMP = 2.376
 
-    TAX = [
-        (1073.0, 1.5),
-        (1073.0, 2.0),
-        (1073.0, 2.5),
-        (1073.0, 3.0),
-        (1073.0, 3.5),
-        (1073.0, 4.0),
-        (1073.0, 4.5),
-        (1073.0, 5.0),
-        ( 'inf', 5.4),
-    ]
-    STD_DED = {
-        '':                       0.0,  # Exempt
-        'single':             12400.0,
-        'married':            24800.0,
-        'head_of_household':  18650.0,
-    }
-
-    def _test_sit(self, filing_status, schedule_pay):
-        wage = 5000.0
+    def _test_sit(self, wage, filing_status, additional_withholding, schedule_pay,  date_start, expected_withholding):
         employee = self._createEmployee()
         contract = self._createContract(employee,
                                         wage=wage,
                                         state_id=self.get_us_state('MO'),
                                         mo_mow4_sit_filing_status=filing_status,
-                                        state_income_tax_additional_withholding=0.0,
+                                        state_income_tax_additional_withholding=additional_withholding,
                                         schedule_pay=schedule_pay)
-
-        payslip = self._createPayslip(employee, '2020-01-01', '2020-01-31')
+        payslip = self._createPayslip(employee, date_start, date_start + timedelta(days=7))
         payslip.compute_sheet()
         cats = self._getCategories(payslip)
 
-        pp = payslip.get_pay_periods_in_year()
-        gross_salary = wage * pp
-        standard_deduction = self.STD_DED[filing_status]
+        self._log('Computed period tax: ' + str(expected_withholding))
+        self.assertPayrollAlmostEqual(cats.get('EE_US_SIT', 0.0), -expected_withholding)
 
-        mo_taxable_income = gross_salary - standard_deduction
-        self._log('%s = %s - %s -' % (mo_taxable_income, gross_salary, standard_deduction))
-
-        remaining_taxable_income = mo_taxable_income
-        tax = 0.0
-        for amt, rate in self.TAX:
-            amt = float(amt)
-            rate = rate / 100.0
-            self._log(str(amt) + ' : ' + str(rate) + ' : ' + str(remaining_taxable_income))
-            if (remaining_taxable_income - amt) > 0.0 or (remaining_taxable_income - amt) == 0.0:
-                tax += rate * amt
-            else:
-                tax += rate * remaining_taxable_income
-                break
-            remaining_taxable_income = remaining_taxable_income - amt
-
-        tax = -tax
-        self._log('Computed annual tax: ' + str(tax))
-
-        tax = tax / pp
-        tax = round(tax)
-        self._log('Computed period tax: ' + str(tax))
-        self.assertPayrollEqual(cats.get('EE_US_SIT', 0.0), tax if filing_status else 0.0)
-
-        contract.us_payroll_config_id.state_income_tax_additional_withholding = 100.0
-        payslip.compute_sheet()
-        cats = self._getCategories(payslip)
-        self.assertPayrollEqual(cats.get('EE_US_SIT', 0.0), (tax - 100.0) if filing_status else 0.0)
-
-        contract.us_payroll_config_id.mo_mow4_sit_withholding = 200.0
-        payslip.compute_sheet()
-        cats = self._getCategories(payslip)
-        self.assertPayrollEqual(cats.get('EE_US_SIT', 0.0), -200.0 if filing_status else 0.0)
-
-    def test_2020_taxes_single(self):
+    def test_2020_taxes_example(self):
         self._test_er_suta('MO', self.MO_UNEMP, date(2020, 1, 1), wage_base=self.MO_UNEMP_MAX_WAGE)
-        self._test_sit('single', 'weekly')
+        self._test_sit(750.0, 'single', 0.0, 'weekly', date(2020, 1, 1), 24.00)
+        self._test_sit(2500.0, 'single', 5.0, 'bi-weekly', date(2020, 1, 1), 107.00)
+        self._test_sit(7000.0, 'married', 0.0, 'monthly', date(2020, 1, 1), 251.00)
+        self._test_sit(5000.0, 'married', 10.0, 'semi-monthly', date(2020, 1, 1), 217.00)
+        self._test_sit(6000.0, '', 0.0, 'monthly', date(2020, 1, 1), 0.00)
 
-    def test_2020_spouse_not_employed(self):
-        self._test_sit('married', 'semi-monthly')
-
-    def test_2020_head_of_household(self):
-        self._test_sit('head_of_household', 'monthly')
-
-    def test_2020_underflow(self):
-        # Payroll Period Weekly
-        salary = 200.0
-
-        employee = self._createEmployee()
-
-        contract = self._createContract(employee,
-                                        wage=salary,
-                                        state_id=self.get_us_state('MO'))
-
-        payslip = self._createPayslip(employee, '2020-01-01', '2020-01-31')
-        payslip.compute_sheet()
-        cats = self._getCategories(payslip)
-
-        self.assertPayrollEqual(cats['EE_US_SIT'], 0.0)