Facing issue while using Expression Language(EL) in page composer for oracle fusion expenses

1st - There is a field(DFF) at Expense item level which should be enabled AND mandatory only when expense item is older than 60 days (Creation date - Expense item date)

I have written logic on that DFF using EL using sandbox with page composer as below

#{(bindings.CreationDate.inputValue - bindings.StartDate.inputValue) > 10 ? true : false} but it seems this doesn't work

2nd - When i set a field(DFF) required using sandbox , it gives only Atrick but doesn't really behave like mandatory. It allows to submit report without giving any value.

3rd - I have written logic at expense item line level if Field(DFF) at header level is not equal to field at line level (DFF Project Number field) then one HTML Message should come else nothing should come.