This makes a lot of sense - for wingshooting. "Close range" in wingshooting is 20 yards instead of 40.
So you have your chokes at 30 and 40 - one for somewhat far and one for a lot farther....
I saw a Perazzi pigeon gun ( the live box bird type) with fixed chokes of 28 and 48 - open to stop, tighter to obliterate..........