I don't wish to debate that raise/jam flop is the way to go here, however I'm curious about calculating the equity. It seems that this logic should apply to all situations of this nature but nobody here does this in posts as far as I'm aware.

I propose that if you shove, you can not use the range you place villain on to calculate equity if he calls. This is because you'll be shoving a further ~7 into the ~5.5 pot.

7+5.5=12.5.
required equity for villain to call is ~56% ..feel free to correct my math, I know I haven't account for everything and its not exact. I'm just saying in some situations your going to see overpairs and big flush draws fold. Which will dramatically reduce our equity for when we do see this to the river