The cohesive model used in the bed model is different than that used in the bank model. The bed model removes sediment by mass. Mass is removed per area, per time in response to a force (e.g. N/m2-hr/Pa which translates to the slope of the relationship between mass removed pere area per time and the force, which is 1/time). In the bank model a volume is removed in response to a force, so the units are Volume/force-time (e.g. M3/Pa-hr).
This difference is because bulk mass is removed from the bed and applied uniformly over the bed. The bank model shifts each node laterally, independently. Therefore, a "volume" is translated into a lateral shift, per node.
The following table provides conversion factors to move between SI and US customary units.