Just generate a new random value instead of incrementing

Even that is overkill if all you're interested in is if a change occured.

What’s an easier way? I’m assuming they want the app to be able to detect when “a”, was copied, then “b” and then “a” again, so just looking at the value probably isn’t enough.

I don’t think an app should have access to that (without some sort of very special permission).