Better Males with worse female rule

[Rikoku]

So i read somewhere that you should never ever breed a higher priced/better gene female with a lesser gene/lower price male. I was wondering if this was a thing because I havent really found this rule anywhere but the one source that i dont remember off the top of my head. If this is true could you please explain it to me? Why is this done? Is it true across the board or only for specific morphs? Is it not true for any morphs? (i.e. bananas?)

Here is the article you are talking about, I was just reading this yesterday.

http://ballpythonbreeder.com/2012/02...thon-breeders/