I feel kinda dumb now. Holy crap that was easy, clock is getting put away. I should probably play with it some more and see what it can do...
Trust me, I had a similar moment, I bought my first Kill-A-Watt many years ago, and it wasn't until several years later, I finally figured out to use it instead of an inductive RPM probe to tune in generator RPM.. I was like, this whole time I already had the better tool right there. I didn't make the connection even though I skimmed past the Hz screen all the time to see 'watts' screen... Now I don't even check the RPM, because I know it's right when the Hz is right, so whenever a neighbor asks me to fix their generator I always bring my Kill-A-Watt with me in my tool pouch. I live in an off-grid community so I fix a lot of generators out here on the co-op.
Another trick on generators, if the volts is out of spec, many of the AVRs (voltage regulators), have a little pot on them (set with tiny screwdriver), usually accessible, if you remove the glue covering it up. Can clean the glue off, and fine tune the voltage if it needs it. Often times I find that the cheaper consumer grade generators are running too low of voltage. If there is no accessible pot on the AVR, the aftermarket replacements have them on there (at least all the ones I've ever put on them when they fail)..
Usually when doing new brushes, many of them have the AVR right next to it on the alternator (under the end-cap where the brushes are), so I tune it in for best correct voltage between both the 240v and the 120v readings, because many times if I go all the way to 120v on each leg to neutral, the I might be up to 249v on both legs, so I find the compromise between both, like say 114v on the low and 242v on the high.
I try to check the volts with around half-load on them and then check them again with no load (make sure they don't go too high due to cheap AVR). Oh, and only set the voltage once the governor RPM (Hz) has already been tuned in to 60 Hz, since too low of RPM can also cause lower voltage.
Also, the above, is all based on non-inverter generators. The inverter generators always maintain the set voltage and Hz, decoupled from RPM...