Well, you hit a sore point, The little CECB box, you can type the physical channel and the virtual channels programmed or not programmed will show up.

On a 55" System 6 "Smart", very dumb TV, nothing happens.

it can only delete-all and re-scan. That's are the brain cells it has.

Can it know about an antenna rotator? No.

You can also have for the same physical channel: Say 36
6-2
51.1
51.5
51.101

There was some major shifts, at least two in the Philadelphia area. I don't know if scan and add would have worked for one of them.