Hi Bill,
It looks like you have found a few options to try and automate this.
I have seen where an employee gets a letter from the CRA for an authorized Annual Deduction and the letter usually states the amount that needs to be put into the system for Cumulative Averaging, which is what GP uses for Taxes.
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(Cards >> Payroll - Canada >> Employee >> TD1 Values >> Tax Credits)
Check the Update button, and enter the Authorized amount.
Since GP uses Cumulative averaging on its tax calculations, according to the document it would tell you that $XX,XXX would be entered into the Authorized Annual Deduction Amount in this field.
Authorized Annual Deduction -
Annual deductions such as child care expenses and alimony payments, etc authorized by a tax services office or tax centre. The amount entered will represent the annual amount of the authorized deduction. The system will use the value entered here to reduce the employee's annual taxable income.
Authorized Annual Tax Credits -
Other federal tax credits, such as medical expenses and charitable donations authorized by a tax services office or tax centre. The amount entered here will represent the annual amount of the tax credit. The amount entered here will be used to reduce the employee's basic federal tax amount.
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If your letter from the CRA does not fall under this, then my recommendation would be to make the adjustment manually after calculating the checks.
Transactions >> Payroll - Canada >> Adjustments >> Detail Adjustments
Use the Payroll Detail Adjustments - Canada window to add or modify employee deductions for taxes, Employment Insurance (EI), and Canadian Pension Plan or Quebec Pension Plan (CPP/QPP).
This is only one employee, and it is only for a couple of months by the sounds of it, so it would not be too difficult of a process to manually make this change after calculating the checks.
Thanks!
Isaac Olson
Sr Support Engineer
Microsoft Dynamics GP