75k here.
Recently I SDC'ed BOS-SFO to BOS-SEA-SFO as I needed to get to SFO sooner.
Did this through Alaska text line.
I was asked to pay the difference in taxes ~$9, which I didn't bother to resist. Surprised text line processed my payment using card on file, too.
Is this tax thing something new? I did most recently sdc'ed LAS-SEA-BOS into LAS-PDX-LAS-BOS to squeeze out my 12th segment last November with no problem.