If you do owe a Penalty for Underpayment of Taxes, and you entered your Estimated Taxes paid in the interview, the total of these and Tax Paid that was entered into the program, should show on Line 11 of Form 2210, as you mention.
However, if you don't owe a penalty, Line 11 may be blank and not allow you to make an entry there, if you're using Forms mode.
When TurboTax mentions Line 19 (Penalty Amount) they are referring to the combined total being used in the calculation, but I agree that the wording in the instructions could be confusing.
Here's more detailed info on Form 2210.
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