Why does Rally even track "accepted after iteration"? What if it was 3 months later? A team should then use that data for future planning, even though it takes them months to get something Accepted? Doesn't make sense.
Just simplify it. If it's Accepted in the sprint count it. If not, don't. Easy. This is the only way to accurately gauge what a team is actually completing within the sprint (I'm not talking about "value"...strictly for planning purposes). Anything else is just a count of what's been completed no matter how long it took...and that's worthless information from a planning perspective.