I know I'm going to be crucified for saying this... but it's true...
You really cant "powerfeed" a ball python. Theyre not designed the same way a boa is so you dont have a great amount of health issues from doing it. You can "overfeed" a python though. That would constitute double feeding in shorter than normal time periods. If you feed smaller than a normal sized meal to a ball you can feed it more often. I wouldnt recommend feeding huge meals constantly, that's just ridiculous. A python will digest almost anything it can as fast as it can. Obviously, if you feed it every week it's going to stay at that digestive pace. If you feed every three days it will set itself to that pace. You could feed it pinkies everyday if you wanted to.
As for the ball python "plateau". I would say all animals plateau at some point. However they never stop growing... but they will get to a size and slow down. I have a 3000g (on empty) female ball that has gained about 300g in the last year. I cant see the change and she hasnt gotten any longer, but she has put on weight according to the scale.
I would say that if you wanted to feed her more you'd be fine. Before you feed her an extra rat or a bigger rat, try feeder her every 7 days instead of 10 days. If that doesnt work to put on weight, drop to a medium rat and feed her every 4 days. This is, of course, if you need her to put on weight. She'll get fat in a few months for sure.
Hope this helps you out.