TB is Tremolo-spaced, SH is standard humbucker (older Gibson tuneomatic) spaced.
Both types of bridges have a slightly different string spacing, and the idea is that the strings should pass directly over the center of the pickup poles. To do that, you need to make pickups for both string spacings.
Some years back, Gibson changed the angle of their TOM such that trembuckers will line up with the strings.
If you're getting a sound you like from the pickups, there's no need for concern. Personally I prefer a non-F-spaced Distortion in a Floyded guitar. When the poles line up perfectly I detect a touch more articulation but a lack of "grind", especially in the higher strings.
I'd rather have the grind.