From one extreme to the other - electrically speaking

I left two RV parks this past month because of low voltage. When I first connected i read 102-104 volts at pedistal with no load. Got refund and went on down the road. The lady at one park ask if I had "one of those things" between my cord and the pedistal and if I did I should remove it because they cause problems. Found a mobile RV tech next to where I was going to park and ask him if there was a better location in the park for power. His answer was there if no place in this park with good power.