cavie,
Not all autoformers are created equal. Mine does three levels of boost and one of buck. I have added surge to it that is head and shoulders better than the offerings from SG or PD. It was cheaper than the SG and PD offerings.
The surge ems disconnect power at 103 and 104 volts. 107 would be the lowest I'd operate the roof air conditioner on. And when it is 40 C (101 f) outside I would want to be able to run the roof air safely. I have boosted from 97 volts on my unit--and that leaves the 3rd level of boost (90 volts) ready to switch in.
As I said before, low voltage is the culprit most of the time. I prefer to correct the voltage rather than be left relying on my "on board" power.
My power system is (when needed):
30 amp shore power-->autoformer-->limit demand to 24 amps-->load support-->RV.
I always check the pedestal voltage and polarity under load before plugging in my RV. I'm in a 30 amp service.