they doesn't work with bob's belts, in fact, your mod makes them do weird things.
without your mod, the speed starts at 12.5, and increases 12.5 per tier (12.5, 25, 37.5, 50, 62.5, 75). Those are the expected speeds for bob's belts
however, with you mod, speeds go crazy: 12.5, 15, 30, 60, 62.5, 75
first one is the basic transport belt, added by bob, prior to yellow belt, and the last two are also from bob's mod, that points out that this mod is not working with bob's belts, but the most weird part is that the vanilla belts start at 15items/s
The before version 0.16 the base speed (both sides of yellow belt) was 12.5 items/second, but since 0.17.xx the base speed is 15 items/second.
Bob's mod must have speeds: (7.5 for gray belt) 15, 30, 45, 60, 75 etc. https://wiki.factorio.com/Transport_belts/Physics
Bob's logistics also adds miniloaders for the two tiers it adds, if you have miniloaders. And, well, the Turbo miniloader (Tier 4) is only slightly faster than the Fast miniloader (Tier 2). Express (Tier 3) is double the speed of Fast, as expected.
Ultimate miniloaders (Tier 5), are for some reason slower than Turbo as well.