No. See, it doesn't work at all like that. Not in HEM. Not on the sites. Can someone back me up on this so we can move on?
That's why you're getting discrepencies in your own figures. The figures aren't random.
Whereas when I'm working it out I can get it down to the cent, but (incorrectly) including JP rake.
As I said earlier the formula is:
Total rake in a hand / everyone who contributed to the pot (including both blinds 100%). And you only get that portion assigned to you if you personally contributed. Hence contributed.
It's nowhere near as simple as "my pot got raked $x, so I get back 30% of $x". Go check a mini-session where you didn't win a single pot. Guarantee you you will have non-zero rake (except if no hand saw a flop where you put money in the pot).
Rakeback is nothing more than the part of rake assigned to you (via contributed or dealt methods) * 0.30.
HEM is working it out correctly. They just need to add a different column for JP contribution (hell, it would be better if everyone stopped calling it rake) or at the very least just ignoring it from rake.