Thank you very much for your help. Following your steps, I was able to pinpoint and fix the problem, as follows:
First I forced TurboTax to switch me to itemized deductions. Once I'd done that, I could see a list of itemized deductions, and I could compare the amounts the software was crediting with the correct amounts from my 1098s.
At that point I could see that the problem was that the mortgage interest from a second home was not included in the itemized deductions. I tried deleting and reentering that 1098, but the mortgage interest was still not included. Then I tried deleting and reentering both of my 1098s (primary home + second home), and that fixed the problem. I'm good to go now, and I really appreciate your help.
-Raymond
