I asked this after looking up a tab for Thunderkiss 65 because I was having difficulty working out the bass behind the guitar solo, there was something a bit funky going on. First tab I found showed straight eigth root notes, second tab showed it the same as the chorus riff which it clearly isn't, third tab was close but definitely simplified quite a bit.
Even on websites where you have to pay they're rarely correct.
The Sabbath book I've got which has errors is by Hal Leonard