Statements are received after Clearing house. That means all your buys vs sells are matched up. It's not AMP employees making billing mistakes. However if you think there is a discrepancy you should call them. I was on their chat the other day and it was fine...
By the way for those using CQG, have you checked the connection with Desktop CQG web platform during the issues? Can it be considered a backup to manage open positions if SierraChart -> CQG fails to connect?