Sorry Mike I don't have the details. The foundation board approves any expenditures so it may be that the publicity for the raffle raises more money than they spend. The foundation is responsible for scholarships, grants etc. I would imagine it's a tax thing but a call to Mandee at HQ would resolve any questions, that's her gig and she does a great job managing it.
Also this explains what the Foundation is and does
http://amablog.modelaircraft.org/amafoundation/