Originally Posted by
Ditto
This happens every now and then... but normally you would get the original mileage (for DOD type upgrades)
I had several KL/AF flights where I got "M1" as the earning class, even though the ticket was on a cheaper bucket.
Happened to my friend as well on KL flight from AMS to EZE, M1 earning class, on May. He got quite some more miles compared to the initial fare, for a relatively cheap DOD upgrade.