the majority of powertab tablature out there is copied straight from a book or taken from a GP5 tablature and made for powertab.
but then again even tablature (official) books have things wrong or not how you would play it and indeed not in the right position the artist would play it.
when i used powertab i never found any songs that came the wrong way and were tabbed pretty accurate i just played it how i thought it sounded if there was a bit tabbed out different to what i knew .