I can understand but there is a concern in the sytem give some time to check the feasible options.
You are saying in general planned working days are 25 excluding holidays but employee is joined on 11th of the particular month holiday is on 01st May which lies before joining date we can not count this holiday itself.
Since payroll won't consider holidays while calculating working days i.e planned(26) and actual(18) some how we can count holidays which falls after joining date now problem is falling holidays on before joining date.
We will have to look for work around where number of holidays per each month needs to be stored some where in the system accordingly we can write a PCR.
Give some time to check feasible options.
Regards
Venkatesh