Update. I called Customer Care today 4/26/21 (they are closed on Sundays and re-opened Monday 8AM PST) and after a 20 minutes hold after giving them the details, they offered to refund me the fare difference on the ticket to the original form of payment. In addition, compensation was either a $75 voucher or 3,000 MP points. I took the voucher since I think MP points are way less than 2cents per point. For what it's worth, I'm an AS MVP.

I asked the rep what the fare difference would be but she said she didn't know since this matter was being sent to the accounting department (which could take 7-10 business days). I will update one last time when I get the fare difference to see how they calculated it.