This will sound sort of stupid, but the bottom line is... it depends on your goals. 

Everyone's goal is to have fun.  But what is "fun" for one person is different for another.  Fun for me has changed over the years.  When I was younger, fun was being competitive.  That meant learning everything there was to learn at each level.  BY DEFINITION, that means flying in a class until you're winning.  It's not just learning the maneuvers, but learning how to win.  It's being prepared, mechanically, mentally, etc.  It's learning the maneuvers, but it's also learning the presentation. Learning what scores.  Learning to calm your nerves.  Learning ALL conditions...  You get the idea.

Now... 20 years later, FUN is still being competitive, but beating Andrew isn't in the cards, so fun is also learning new things, trying new equipment, improving every season, and socializing with now life long friends who share my love of this hobby.

Long answer to a short question.  But if your goal is to be competitive, than I would suggest not moving up until you're winning consistently in your region, and are "in the hunt" at the nats.  Else there is clearly still something to learn in that class.