The order in which things are done is this:

1. You enter all medical bills (reimbursed by insurance or HSA or not).

2. You enter your insurance reimbursement, which is subtracted from #1.

3. TurboTax automatically carries over all HSA distributions, which are also subtracted from #1.

4. Any remainder is applied to the 7.5% floor, and the excess (if any) is reported on Schedule A.

If you are looking at some number on the Deductions & Credits screen, ignore it - TurboTax often displays the total of what you entered on internal screens, but the only real number is on Schedule A.