OK, the last I read has to do with Direct funding and Indirect funding. The number of years you qualify for direct funding is determined by the first residency program you enter. Then if you switch from, say a 3 year program to a different program that takes 4 years, you still only get 3 total years of direct funding. As for doing a whole 2nd residency -- I think you can still qualify for indirect funding, but economically most programs want to fill their slots with residents at direct funding because it's a higher percentage.