The CAHA/SCAHA system which reaches its maximum level of expansion at U12 is so confusing and full of options, it's literally almost impossible to gauge where your kid is at because there just isn't that much competition at birth year. There are far too many PW teams between AAA/AA/A/BB and B. With A you get 18-20+ teams, so it's not like there is a lot of parity. The top few teams barely lose a game, whereas you have 12 or so teams that don't make the playoffs, and know they won't before the season is 1/2 over.
I don't really see what the big hurry is to get to PW. It's probably the worst version of hockey there is. Lots of puck hogging and end to end rushes, and some of the worst reffing you will experience. If a kid has any modicum of legal body contact in their repertoire, expect them to log major penalty minutes especially if they are larger than average, and enjoy the comedy when one of the play-up teams is matched against a Major year team. Nothing sadder than seeing a kid execute an angled rubout perfectly, only to dump a kid half their size coming off the boards with the puck and get whistled down with a 2 & 10 for head contact.
I can't see why someone thinks it helps with development for a kid to play on a team that wins 5-6 out of 15 games and has a -30+ goal differential in PWA and thinks that just because they played up and survived getting their ass handed to them, that it's made them more competitive. It's an incontrovertible fact that as you go up in age level and level of play the amount of time the average player controls the puck becomes shorter and shorter. Again, why seek that out, especially if your kid is going to have to spend the entire year struggling when they are on a far more gradual maturation curve. You still get 2 years of PW regardless and 2 is plenty.