How to Add a CRA Approved Tax Deduction at Source

Hello,

We have recieved a 'Reduction of Income Tax Deductions at Source' for one of our Canadian employees. This is the first time I have had to set one of these up in JDE; I have tried entering it under the 'Tax Overrides' - 'Other Tax Credit' but the taxes deductions are still to high when comparing to PDOC.

How should this be setup in JDE to adjust the F1 amount?

Thanks!!