since it had caught on fire at a Matehuala RV park
A few years ago I tested all the outlets at Las Palmas in Matehuala and found the vast majority to be improperly wired - wrong polarity - no ground - etc. A lot of bad juice in that park. Always check outlets for correct polarity and ground before plugging in. We see a lot of this in Mexico. Many of these places were not wired by trained electricians. Some of the people who wire these places think they know what they are doing but they don't.
I was under the impression that the Hughes only raises low voltage but does not lower high voltage. I don't know. At today's rate of exchange an ISB Sola Basic 4000 for around $200 would be a good buy in my opinion.
I can't really say anything about what might cause a surge protector to go bad. I think you really need one but have no idea where you might get one in Mexico. Lots of people do get away without them.