Used to be some flexibility but a few years ago they seem to have decided no more exceptions.

Hence the need to use the many tricks described on this board such as
- starting and ending the ticket on opposite sides of the same country, the gap between end and start points doesn't count. For example SYD-America-Europe-Asia-PER liberates the 2,000 miles PER-SYD (for which you have to buy a separate ticket of course.)
- using one-stop journeys on the same flight number, so they count the direct mileage from start point to end point rather than the two segments. For example GRU-ORD-SFO on UA842 counts as 6,470 rather than 7,068 (5222+1846) miles