Monty had his anal glands removed because he developed an infection that did not clear.
They had to make an unusually deep incision and I was warned at that point that he may be incontinent of feces. Fortunately that did not happen, he was such a good dog indoors that he would have been so upset by the loss of control.
Removal is not something to be undertaken lightly and I am surprised that it was suggested for a dog that was not having real problems with impacted glands.
Scooting when the gland is empty may well be due to slight soreness. Wipe the offending backside clean with baby wipe & smear on a little vaseline for a few days.
Cavaliers......Tommy Tuppence 2000-2012 and a half share of Faith.
Japanese Chins.... Dandy, Benny, Bridgette and Hana.