Do snakes overeat?

[Skiploder]

They are supposed to eat 10-15% of their bodyweight every 1 1/2 - 2 weeks. Monty was eating about 3%. I've corrected the problem and he is now eating a 100g rat every week and a half (still smaller than what he should be eating, but the next size up is 180g). He weighs approx. 1138g. He should be eating 113.8 - 160.0g.

Ah.

Do they snakes know they are supposed to be eating 10 to 15% of their body weight?

Is this for all snake species?

Is it dependent on enclosure size?

Activity level?

I'd love to know how this percentage is calculated or how it was arrived at.