The system calculates your entitlement for period based off your contract hours and FTE hours, for example, if you work 20 hours over a 40 hour week, and you have 28 days paid leave, the system will calculate this by the following:
28 days (FTE Holiday) / 40 (FTE Hours) * 20 (Contract Hours), which will give you a new allowance of 14 days.
This will also do the same if you have your holiday allowance in hours instead of days:
175 hours / 40 FTE * 20 contract hours = 87.5 hours
The formula is: FTE (holiday entitlement) / FTE Hours * Contract Hours.