In recent years, TurboTax developers have been adding various checks for over contribution. I'm going to experiment with TurboTax for the past few year to see when TurboTax started checking the combined contributions to plans subject to section 402(g).
[Edit]
2022 TurboTax is the first version that had any checking for over-contributing based on W-2 box 12 entries and it implemented the check on the combined amounts subject to section 402(g) as does 2023 TurboTax.
