Flex Time vs Full Time

At our hospital we get benefits with flex time which is 40-64 hrs a pay period. Other than the amount of pay would there be any advantage to full- time? Can they force overtime on a part time basis? Just wondering. I know our hospital's policies may be different- I was just wanting a general idea of how things worked in your facility and if there were extra advantages to full time other than take home pay. Thanks in advance!
Hospitals can do WHATEVa they want. It's sad, but true.