Originally Posted by
jackywhatever
.....If I manage to do an instant upgrade for inbound, and then instant upgrade on outbound travel, how will mileage be deducted? 40000x2 or 70000?
Instant upgrades are processed at the airport. It has a different paper based procedure and is one way only.

There is no way to do a return instant upgrade.

The return mileage is only applicable if you can confirm return upgrades before mileage deduction.