Disk Quotas and Drop Boxes

I have users set up with disk quotas on their folders… when they turn in assignments to the teachers (drop boxes) this limit stays with them because they are the owner. Is there anyway that once a assingment is turned into a dropbox (just another folder) that the disk quota on that user would reflect the change. For example mary has a 25mbs of storage she has used 5 mbs on an assignment so she is left with 20.. now when she turns this into the drop box folder she is back up to her original 25. Sorry for being pedantic.

GC