FM to find out how many payrolls with deductions are left?

I've been looking for a FM that will tell me how many pay periods are left that will have deductions taken out of them.

For example, bi-weekly people get paid 26 times per year, however, benefits deductions come out on only 24 of those.

I need to see how many payroll periods are left that will include those deductions.

I've been using HR_MX_GET_PAYROLL_PERIOD, but this doesn't take into account that some periods don't have dedcutions.

will give points!

thanks,

rob.