PCR writing

Hi Experts

I am new to writing PCR's . I need help for the same.

Scenario is:

This should work either in the case of leavers or in the March payroll (financial year end payroll -period 12/YYYY)

employee opts in starting of financial year                                                                      :     wagetype XXXX 

He claims during the year                                                                                             :      wagetype YYYY

If he is a leaver or end of financial year in case of active employees balance amt should be paid as wagetype ZZZZ = (AMT XXXX- AMT YYYY)

Could you please guide me in putting conditions and the logic for the above...

Thanks

Seema