That is not even close to being a done deal. I'm sorry that they misled you. Right now the AOA is in talks with the NRMP about possibly combining the two matches. If all goes well, it'll happen, but there are some at the AOA that don't want to give up control over their own match.
If it does go through, though, you'd be able to rank MD and DO programs together in a single list. This would allow people to have a chance at MD programs & still apply DO without being pulled from the MD match. (as it currently works)
I'm on an AOA committee working on this issue, so that is where my info comes from. This is not the only committee working on this, but as of 2 1/2 weeks ago things were barely creeping along.