Submitted and accepted via TurboTax e-file yesterday!
We spent a while on the phone with a TT tax person (CPA) with whom we shared our screen and who reviewed forms 1040 and 2441 to ensure that they were correct. We are also MFS for IDR purposes, with one kid, $2500 set aside in childcare FSA.
We had the full amount of our kid's daycare in Part 1, the full amount in Part 2 box C, an X in Part 2 box 8, $2500 in Part 3 line 12, $2500 in Part 3 line 14 (carry-over, which comes from the childcare question block), and a 0 in Part 3 line 25. I don't know if that helps or not.
According to the TT person who helped us, we didn't technically get to use the $2500 last year as a dependent care tax benefit beyond the money having been set aside pre-tax due to being MFS, which is why it is carry-over (line 14). But in our situation, the total cost of daycare so so so far exceeds any FSA benefit amount that carrying over wouldn't affect our tax liability in 2019. She explained that for MFS, the FSA is a pre-tax amount that is a deduction (reducing the amount of taxable income), but MFJ using an FSA *also* get a tax benefit that is a credit (reducing the amount of taxes paid on the taxable income).
It took 3 long phone calls to TT, but our returns were accepted yesterday. Hopefully this information helps some of you.
Good luck, everyone!