They're the same genetic mutation.
Some people say that butters are more yellow and lessers are more creamy, etc etc. Sure, they can be these things, but lessers can be more yellow than some butters as well and vice versa with the creamy coloration.
Any lesser/butter snake that looks different is due to the variation of the individual, not the morph itself.
Lesser/Butter and their combos of equal quality should be priced roughly the same.
And combos should have the same name and lesser/butter noted..