I have the MAC 208, which is a 10' box and what we did this year was placed the AC cover on, and then also had a vented camper cover from the dealership overtop. While it didn't have a cutout or a spot for the AC unit, it sloped over nicely to help the rain shed off of it.
Don't forget to lower the tongue jack to create a slope too. One day I came over to check the camper and found a puddle of water infront of the AC unit on the roof, as the cover created a little pool for it to stay there as it rose up over the AC unit. Lowering the tongue jack let the water run off the front of the camper.
My AC unit is located towards the back, so I didn't have the same issue on the back side.
See pics of my cover here: