Originally Posted by
cj_000
Sadly, they do not. It is the base fare that counts towards mosaic status multiplied by 3.
For example, if you spend 500 on a flight, breakdown is $400 for the fare, $50 in taxes, and $50 for an even more space seat, you will receive the qualifying spend on only the $400, netting 1200 points towards qualification.
You are correct, but in this case, the second seat is not an add-on. You are paying the base fare for both seat 1 and seat 2. See the link I provided above.