You would multiply by the residue number, assuming I can latch the current number somewhere. Sounds like a synthetic Stats value, much like Folding's Score value, for use in table and graph outputs.
This is possible, though it would make our numbers disagree with the project numbers. Once Scott gets back from the family vacation, we will be testing new stats code on his server. We could play with a dFold Stats value sometime after that.
There are a couple problems though, check the dFold project to-do list. They plan to mod the server so the previous protein units will still be accepted for a couple days after a protein change. This would produce funky numbers. Also, once Casp is over, they plan to go back to long-term crunching on a single protein.