I'm just platinum so upgrades are hard to come by out of MIA. So we fly MIA-BOS and MIA-SFO often using instant upgrade fares. It seems these fares have just exploded recently. Two weeks ago I started to book a MIA-BOS trip, put it off, then went to book yesterday and the instant up fare was $1027 as opposed to the previous $647. This is on all flights and dates and seems to be permanent (at least thru Jan 2012). On the other hand, MIA-SFO instant up is $497 on all flights for our travel dates. Did I miss something about fare increases as to me it doesn't make sense. Thanks.