Originally Posted by gyldenlove
That is true only of the higher round picks. In the 7th round teams often get picks based on total exchange, so losing 7 and only gaining 2 can easily net a 7th round pick or two even if none of the individual contracts are quite high enough to warrant a pick.
This is correct--I didn't mention it because it only applies to a subset of 7th round picks, and I wanted to keep things simple. I don't recall a team getting two 7ths for net value but I don't know for sure off the bat if that's happened before.