Maybe if I start a separate thread, I'll get an answer.
What does a tester determine? What does 140 mean? What if a bat test is under or over 140? What does that really mean? Looking for a clear explanation of what a tester really does.

140 is just the set mark that they came up with for senior bats, just as USSSA had a mark of 220 at one time and now has it set at 240. This link below shows a USSSA bat tester:
https://www.barrelcompression.com/documents/G4-USSSA-Barrel-Compression-Fixture-instructions.pdf

Just because a bat is below the 140 mark does not mean it's altered it just means that it does not pass the 140 compression mark. The link below answers some questions:
https://www.seniorsoftball.com/?news&story=2020

You can also google bat testing and there are plenty of links that will explain what bat testing does.

Thanks Bones505, curious to see where this goes. Does not sound like an exact science, specifically for folks who have had their bat for awhile and it fails due to usage only. Hopefully it is not another gimmick to force folks to buy new bats like when they changed the approved logo. Just sayin.