This is on 1.12.2 v1.1.4b170, but may affect other version too.
Currently it seems like no matter how high the chance multiplier for soils is no drop that is listed as being produced once (like vanilla logs) can be produced multiple times per cycle.

Could you make it so that high drop chance (e.g. 75% and 400% increase = 375%) would give 3 items guaranteed and 75% chance to get a fourth?