This is key to the confusion in my mind of your post? If I were to substitute "tax code" for "plan" in your post it would make sense to me for as I have said more than once, RMDs have to be taken from each tax code. It makes no difference as to which investment account (Stock Account), ILB, Equity Index, REA, etc. as long as all of them are in one single tax code such as 403-b or IRA.
When you call I suggest you ask your question in term of "tax codes." I have done this several times and always get the answer I have posted several times which is the only reason I repeat myself; I believe what I have posted to be correct.
Ray