That feeding chart is fantastic. Only issue is it doesn't mention that it's really only applicable to juvenile and subadult BPs.
Another thing worth mentioning is that there are far too many variables at play to determine "proper" growth via weight. You want to pay more attention to body structure. They should maintain that triangular shape and be pretty solid muscle. Weight can vary animal by animal drastically, but body structure always tells you what you need to know regarding your snakes "weight".
They also vary drastically before and after going to the bathroom. The "empty" weight (after vacating) is the most accurate weight, but it will fluctuate depending on when the snake ate, pooped, etc...
I figured as much. Bearded dragons, which I have a ton more experience with, are the same way. They have a healthy weight range as adults and that's about it. I guess I'm fine as long as he's eating, pooping, and shedding.