When to move NL25 -> NL50 (Party)

Hi.
My question is when to move from NL25 tables to NL50 tables on Party Poker. I know the standard 25 times buy-in rule (or 30 times or so on). According to the rule it should be somewhere beyond $1250, but...

NL25 are the lowest no limit tables on Party (not including beginners), and because of that they are full of fishes/maniacs/etc. I am devastating those tables, practically never going away with less money, usually earning more (or a lot more) than 10BB per 100 hands.

So will the nl25->nl50 change give me more money or will it just make the play harder?

Grasiu