FTE / Head Count for seasonal and part time employees

Summary: We have hundreds of students working with us during the summer and winter months. Some work a regular full time work week, others work varying hours. Our standard hours are 8 hours per day for 40 hours. I'm tasked with trying to update the FTE for our part time seasonal folks where they don't necessarily work 2080 hours (40 hours at 52 weeks/year). Is updating the working hours and leaving the standard hours at 8 hours the best way to show the FTE.

Content (please ensure you mask any confidential: If on the person management I set their synchronization to "no" I can update their hours of work to 20 hours / week at 4 hours / day. This would show that a student who doesn't work 40 hours a week would equal on .5 of an FTE. Is there a better way to show this?