I think the 10-15% rule is for hatchling (not 100% sure) Ive never weighed the rodents. At first I was freaked out all the time about the right size food but after you have more experience you learn to just look at the rodent and know what is a good size. I havnt tried feeding smaller more often but like I said there is more than one way to do it. If it works for you then go for it.