Don't you think the problem is inside the park with their electrical system and wiring and not with the CFE?
Yes - I do think it is park wiring for the most part - but any and all power companies and various different areas can fluctuate. There can be variations in actual voltage from one street to the next depending on the transformers and other factors. Doesn't matter what country you are in or where you are in that country. There are more reasons than anyone can ever list for why voltage may not be exactly what we want.
The point I try to make and seem completely incapable of doing is that we try to get our incoming power at around or as close to 120 volts as we can. That is what the ISB or the Eco Wise claim to do. The reason for this is the "standard" in the US and Canada is 120. What you actually get may vary but the fact is the "standard" is 120. In Mexico the "standard" is 127 for reasons I do not know. But most of our equipment (everything I can find a label for) says 120.
The point of this whole thread has to do with the idea of using surge protectors (whatever brand) and voltage regulators (whatever brand) to try to protect the equipment we have in our RVs. This is not for everyone as not everyone has all the stuff some of us have. We have a big rig (way too big) with a lot of stuff (way too much stuff) so we try to protect our stuff.
I can get my meters - I have both analog and digital meters and I have them for each leg of the two legs we have for incoming power on our 50 amp system - to read 120 volts by minor internal adjustments to our ISB (which no one should try unless they know what they are doing with electricity). Note that these devices do state that the desired voltage they regulate to is 120. That is what we desire.
I can also hook up my multimeter to check that my other meters are correct. I am almost always right on 120. Our surge protector will cut our power if we go below 108 or above 132 - I know different devices may cut power at different voltages - ours is 10 years old so may not be built to the same specs as today's units.
I do not have a problem if we hook up somewhere and my initial test of the pedestal says 114 or 117 - or 127 - or just about anywhere in-between. I have my ISB and then I get 120. Much of your equipment will survive if voltage is a little high or a little low. I don't think I want to run my A/C compressor motor for too long below 110 - fridge either. If the "standard" really was 110 and the power companies set output to us at 110 and things were not just right we might have some equipment that is sensitive having problems.
We lived on a Caribbean island for 8 years. There were power problems. We had UPS (uninterruptible power supply) devices with AVR (automatic voltage regulation) all over the house for all kinds of different equipment - TV - Computer - fridge - etc. Those who did not had to go buy new equipment every year or so. Not providing adequate power to some equipment is just not very good for it. Other equipment could on forever with no problem. As our equipment becomes more and more efficient it requires proper power supply.