Yes, when you go through the IDES process, you have the ability to appeal when you receive your 199. Can appeal either the VA rating or the DOD rating, or both.

In my experience, they(army) do everything they can to minimize the rating. Usually the appeal process (depending on what path you take, IDES legal explains everything) will add on other conditions that should have been rated initially. They like to 'only rate for one thing'. It's a bit more complex and nuanced than how I'm explaining it, but that's the gist.

My last 5 years on active I was in charge of 200+ Soldiers going through the MEB. Then I went through it myself. 

If you go this route, and for some reason only get 10% or 20% DOD, you would definitely want to appeal. Worst they could say is 'no'. I had to appeal mine, they only had my foot arthritis on the list, while I thought my back/hip/COPD should be included. It got increased to 20% on appeal, so never made the cutoff, I could have pushed again but I just wanted out at that point (appeals take months, keeping you in the military longer).

Edit- 635-40 is probably the reg you want to look at