The Canadian version of the 03 Komfort has the MW and water heater on the same 7355 circuit and the one breaker, but there is only the one black wire going to the bottom of that breaker. There is another wall switch that has three positions for the WH and MW, which are : WH, Off, MW.
The USA version of the 03 Komfort 7355 does not have that, but has a different arrangement for the 120v breakers, and uses 20s instead of 15s a lot.
Perhaps the now gone RV had something like that with a downstream switch between the MW and the fridge, away from the single breaker.
EDit--ok forget that, the MW had its own breaker.