I booked SFO to JNB in flexplus economy, intending to upgrade only the SFO to DXB leg, and I see now that the miles required to upgrade just the first leg are the same as to upgrade both legs!?! (Yet the miles to upgrade only the second leg (DXB to JNB) are fewer). It certainly wasn't his way two years ago when I flew JNB to NYC and upgraded the DXB to NYC leg for around 55000 miles - not the 70200 it now wants just for that leg)

When did they change this? Is there anything that can be done? Are upgrades done at the airport perhaps cheaper?