They usually offer $300 or around that number and it can go up until they get someone. You didn't wait for any extra compensation, you got the best for your situation but if you were at the gate and they were looking for a volunteer, and nobody offered their seats, it could be more than $700, but someone could beat you. Besides, you can not compare that someone got $1000 for a similar situation, each flight is different and sometimes is cheaper for them to bump someone who paid $60 dollar for their seats that someone who paid $300 for the same seat.