When the female is at a healthy weight and starts to build follicles, it will trigger more of a food response as she is wants to build some fat reserves to sustain herself through the breeding season. In the wild, when they are close to ovulation they probably don't eat until the eggs they have been incubating hatch.
back when breeders like Brian, Kevin, and the other pioneering BP breeders were starting out, there really wasn't that wealth of knowledge on breeding these animals in captivity that there is today, so they were figuring a lot of this out as they were going a long based on what they knew of breeding other python species