How can we get leave duration in a period for a specific leave type?

Summary

Leave Hours in an accrual period

Content

Hello,

We have a requirement to prorate fortnightly accrual based on Leave without Pay hours taken in the fortnight when the accrual is run.

E.g If if an employee is on LWOP for a duration of 40 hours of which 16 hours fall in the current fortnight, accrual should get prorated based on eligible work hours for that fortnight. I tried getting duration using the following FF but what i get is 40. Expected result is 16.

DEFAULT FOR IV_ACCRUALPERIODSTARTDATE IS '4712/12/31 00:00:00' (date)
DEFAULT FOR IV_ACCRUALPERIODENDDATE IS '4712/12/31 00:00:00' (date)
INPUTS ARE IV_ACCRUALPERIODSTARTDATE(date),IV_ACCRUALPERIODENDDATE(date)