That part number reference document was from last century.
I know. With the exception of the missing "Q", the recent part numbers seem to follow the part number pattern from that document. I suspect Atmel still uses the same basic scheme.
I went thru a lot of current Atmel app notes & stuff, I didn't come across anything from this decade or the previous decade that addresses the Q.
I can't find anything about it either. It may be time to contact the mother-ship. Hmm, that gives me an idea...
Nor can I find any data sheets the call out a part number with Q in it.