Why do track names and spellings differ compared to other (online) sources?

There can be several reasons for this: The simplest explanation is that there is no official release and no definitive track names or spellings can be found - just like with gamerips. As is usual in the information age, sources may also contradict each other or be inconsistent. In that case, I go with what seems most logical to me.

And sometimes I'm just a bit of a stickler and try to make everything uniform according to my own feelings. For example, I name tracks XXX [Bonus] instead of Bonus Track: XXX. Or I adjust the spelling and write connective words like “in”, “for”, “a”, “with” etc. in lower case. The biggest incision is when I rename tracks. However, this happens very rarely and usually only with the Theme Songs, which I give the name of the respective game (unless the track name already appears in the score). The reason for this is that many modern OSTs follow this convention.