I know every one will not agree with me. But that feeding schedule is perfectly fine. in the wild they may not eat for months.
My adults fall in a feeding between 2-4 weeks.
I do, I feed my two healthy boas every 3 weeks, and both are in great health and body shape. The scrawny rescue one I feed once a week, but smaller meals, just because I'm slowly getting his weight and condition back to where it should be. For the two on the 3 week schedule, it was really based on how often they started looking for food. They are both pretty consistent with starting to roam more at the 2 1/2 week mark. And I've actually gone 4 weeks with Ryuu a couple times, simply because he was still just laying about and not looking for food. He's a perfect "loaf" shape and solid muscle, so I think it works just fine for him.