That is a nice upgrade. I tried to do the upgrade for 2 out of the 4 of us on our last trip and it would not let us.
BUT, when we were at the podium, they were scanning our BP's and they wouldn't scan....... after a few tries, the agent said, "Oh, you are the Dudspizza family, we have given you new seats." At first we were mad as we were traveling with another family of 5 and were all sitting together.... that was until we found out our entire family was upgraded to business class for FREE! They said they needed the seats for other passengers and since we were all A+ members, we got the free upgrade. The only downside was that we didn't get free baggage, but that was ok with us! The kids loved sitting in row 1, even if it was from MSP to MKE! We had to call our friends in the back of the plane to tell them we would not be joining them in coach......... we giggled the whole time and waived at them thru the curtain!