That's the very nature of TAB.
It's open to interpretation whereas notation (score) locks down the finer details if you can be ãrsed to learn it. Even then however, you won't often find a definitive set of notes and measures for a popular song in TAB or even score without paying... and even then it may not be the version that you have in mind.
I use my ear to try and fill in the blanks. A fellow member, @PaulWarning, recommends that you play the tune at a slightly higher speed than normal without pitch correction. That way the bassline is pulled into a more audible frequency range and should stand out better.
Covers... should you aim for accuracy or something that you can handle and still carry it off? Sounds like a new thread in the making.
Remember, what seems right today may not seem so tomorrow. Relax a little and develop your style.