Intuit had an estimated support hold time of 1 hour. I called. Held over 2 hours, still on hold, but I'm not going to hold indefinitely.
I made TurboTax calculate my correct Federal refund by entering half the actual points value, so it counts half of it in two places (i.e. has the correct total, but incorrect line items), and used that figure to e-file an extension via TurboTax. Fortunately, I'm due for a refund so an extension is relatively painless with the information from the completed forms. It seems like the best option - even if I do get through and Intuit can see this issue, they're unlikely to patch and deploy a corrected version of TurboTax Online in the next day.
