I use the paper towel method too.

NOTE!! Do NOT put a "dry" fabric shop towel in for the test. It WILL catch fire - yes flames and a lot of nasty smelling smoke. Not that it ever happened to me....no, and that's my story.

I check the control panel to see if the buttons work.
The light and turntable.
If it heats up my paper towel to steam.

"Inspector's 1 minute test along with a light tester is inferior and should be tested on high for 2 1/2 minutes this should boil water 212°F in most units."
Unit in question will only get to 200°F by their own time and test,
"but that is close enough" they say."

They may have a point. The cheapo microwave in my basement takes much longer to make popcorn compared to the one in the kitchen. I think the power rating has a lot to do with it. If it boils water in a reasonable amount of time, I would have to say it is probably OK.

When I make press coffee (in the good kitchen one), I put 16 oz of water (room temp) and hit 3 minutes and it boils just before the timer goes off. And it's a full rolling boil by then (220 degrees).

I have found that if I use the water from my refrigerator door, it just about the same time.
JF