I found the Tax Payments Worksheet, and it looks like TurboTax double-counted my estimated tax payments. These payments appear in the "Tax Payments Other Than Withholding" and then again in the "Taxes Withheld From:" section, line 18a, "Other Withholding."
I'm filing an Accuracy claim with TT. EDIT: not doing this after all.
Thank you for your quick replies, they were very helpful!
