Wow, thats expensive. Their policy was closer to legacies (UA with free standby or confirmed for a fee) then WN. Now they go the WN route but charge a 150$ fee. Thats steep especially for business people with changing plans. I tend to book later flights and try to catch the earlier one if my meetings end earlier.
At least it gives me some incentive to keep Summit. But if I now use UA I can still do free confirmed standby with my status and on F9 I will end up with the fare difference.