Okay, well that does explain it a little. I would rather have the storage bay open and since I do not need to, "hang meat inside the reefer..." I won't need a Bus Air system.
Interestingly enough, the railroads seem to be switching to RV type roof air for their crews' comfort. I think that is a good sign,RV units are relatively cheap and not difficult to change out when worn out...
As I learn, I just was having a hard time understanding having two motors running simultaneously. The use of 120volt home refrigerators blew my mind, but after understanding the reasons, that too makes sense.