Compare 20 different sites with powerlevels, then report back here how many times they differ. I bet you that you will get 20 different powerlevels for one person, except if on site copied the entire list from another site. Never was said in the show that person A had X,xxx,xxxx powerlevel, save for a couple of times with the use of a scouter.
Other than that, all lists are completely inaccurate. That said, there is also a reason why characters have the powerlevel they currently have in ESF. It's called balancing. How would you feel if you started with Krillin having only like 1 million PL, having to fight Goku with 450 million. Yeah, not great fun...but hey who cares, it's at least following an inaccurate non-official powerlevel list!