TABULAR PROJECTIONS\AGI Detail\Healthcare paid with pretax dollars ?

This concerns the columns on the "TABULAR PROJECTIONS\AGI Details" tab that go into the computation of the "Federal AGI" column. Specifically, I'm trying to understand the value I see in the column "Healthcare paid with pretax dollars", which for me has a negative value of -$3880, so in my case it reduces my AGI by that amount.

Looking for where that negative $3880 figure comes from, it seems to come from the (auto-calculated) Medicare Part B premiums ($2096) + my Medicare Part D & Medigap premiums ($1784).

Why is this value, from these expenses, used to reduce my AGI? I'm retired, with no earned income, and I pay these premiums out of the following accounts (both in real life and in PRC 2024):

Medicare Part B Premiums (auto-calculated $2096): Paid out of my HSA account by including it as a "Scheduled Withdrawal" on the "FINANCIAL ASSETS\Management" Page, with a "Withdrawal Source\Type" of "Qualified HSA". Part B premiums are a qualified healthcare expense for HSA purposes, so the withdrawals are not taxable.

Medicare Part D Premiums & Medigap Premiums ($1784) are entered on the "EXPENSES\Healthcare" page under "Period 5" "Insurance Premiums Beyond Calculated Value", so I assume these are being paid out of the cash account, since they are not included in any scheduled withdrawal.

I don't understand why these expenses are being used to reduce my AGI. What am I missing?

Thanks, Doug