If you're handing in one track at $100 vs 10 tracks at $100 each, it seems a little less of a good deal.
For example (and this is really just as an example - I'm not trying to drum up business on the forum) -- I have a "single" rate at $95 (for FTP delivery). That's a lot more "per track" than a project of 10 tracks would be. Setup, paperwork, yada, yada... Fixed expenses attached per client/project. Those fixed expenses go down considerably as the length of the project goes up.
So - $100 for one track shouldn't equate to $1000 for ten tracks. Unless each track is going to be processed and billed per unit.