Thanks for joining the thread, @jerrym. I'd like to make sure your concern will be taken cared of immediately. 

Since you have already verified that the Transaction Detail report doesn't have any transactions with multiple serial numbers, I'd suggest you contact us. Our Customer Care team can pull up your account and conduct a screen sharing session to review your data and help you further in changing the serial numbers to lots. 

Message us again if you need help with anything else about QuickBooks. We're always here to help. Take care!