Not sure if xbox or pc are having this issue, but i know ps3 is.
When you finish a round and quit no rewards/xp will be added to your stats.
So i'm not even sure if it is really worth playing ranked matches untill dice fixes this.
Heres a link to a battlelog topic http://battlelog.battlefield.com/bf3/#!/bf3/forum/threadview/2832654348035786911/

It is being fixed right now

I'd say no, it's not worth playing for stats/rewards. But you can still play though as if it was unranked.

Same thing happens to me. I would play then log on later and I would have to reacquire it again