I just had a similar experience. FWIW, i'm currently Silver, will be Gold after this next flight - this is a Q fare.

Am traveling to IAH-YYC direct in a few weeks, decided to check on what it would costs to upgrade. To my surprise, it was $59 on the IAH-YYC leg - I've flown this route several times this year and it is pretty elite heavy, not to mention a lot of paid F as it is a big oil route. Very surprising, esp. since the flight is still a few weeks out. BTW, the return leg is $260 - flying Friday morning and returning Sunday evening.