Incorrect Generic 3.125 Flat Mill Stepover?

I’ve decided to poke around in the CNC tools of Luban.

I notice that the generic step-over distance for a 1.5 headed flat bit is 1.2mm, but the generic step-over for the 3.125 headed flat bit is only 0.5mm? Why is this? It feels like an error.

My R&D colleague replied that the parameters are correct. The stepover and the bit size are not linearly dependent. Maybe this pic could help explain:

honestly, it doesn’t make alot of sense. Are the snapmaker larger bits only single cutting edge? I guess why even give a larger bit that is half the speed?