Here are some definitive answers:
Progressive Industries says: EasyStart will work down to about 60 volts so it is no problem for EasyStart. Compressors can operate safely below the rated voltage but will slow and draw more current. If they reach a point where heating causes a problem, the overload will open to protect the compressor. Additionally, there are safeguards in EasyStart that will prevent the compressor from ever running that slowly and potentially tripping your power source breaker. 108 volts AC is unfortunately common at some sites and on conventional generators that are heavily loaded. I would try and stay above 105 to prevent any difficulties.
Airxcel maker of Coleman Mach 15 says: The safe range for these units would be between 108 VAC and 125 VAC. You are on the low end of that, but you should be fine. Voltage usually won’t cause damage until you get below 105, or above 130.
