This is a really complicated question with no easy answer.

1) You're probably ignoring the blinds. At 6max you'd be around -25bb/100 from paying blinds, at FR it's about -17bb/100.

2) When I start raising too many hands "as steals" mine plummets. I think it's because I start cbetting more hands with little to know equity. I didn't try super hard, but going through the HEM articles there was no indication anything was wrong with my game statistically.