I think Delta has slightly changed the federal excise tax here, as mileage amounts are not correlating with the upgrade price on SFO-LAX.

It’s at $84.00 or 7900 miles right now — it used to be, at some point, $84.93, which is rounded up by a cent to meet the 7.5% tax on 7900 miles = $79 USD. Now, though, it’s charging a bit lower than the expected 7.5%.

I wonder if this means this will start to differ more in the future.