Absolutely it's ok. That "rule of thumb" is a decent guideline, but many BPs in captivity are actually over fed and over weight.
For the long term health of the animal smaller meals are better any way.
Think of it like this...
If the animal eats a small rat (say 75 grams for round numbers) every 10-14 days consistently that's roughly 2700 grams of food over 40 meals per year.
That would be about 27 meals if feeding 100 gram mediums. So factor in all the refusals and food strikes and you're lucky if that snake eats 27 times that year.
So long term, the animals fed less food, more reliably, will actually eat more over the course of a year. And their meals will be easier to digest which leads to better health.
Please keep in mind I just made up rough numbers and it's not an exact science, but I think you can understand what I'm trying to say (sorry if my explanation is a bit confusing).
Also, keep in mind, as adults they don't need food for growth, just to maintain their weight. So they don't need to eat as frequently as juveniles do.