the answer to your question lies in IRS PUB 974 which covers the situation when you have marketplace insurance. you can skip worksheet P and start with worksheet W (there are no worksheets Q-V) .
I did several workthroughs and what I came up with is what I paid out of pocket for the premiums + the ACTUAL REPAYMENT is the SE Health Deduction. However, your numbers will be different. I believe your results should be actual repayment + payments.
https://www.irs.gov/pub/irs-pdf/p974.pdf
Turbotax does not include these worksheets in your tax file so you can't review its computations.
part of the complication is that the allowable PTC depends on your income less the SE health but the SE Health deduction depends on the allowable PTC. So Turbotax does successive iterations to get both.
