Pub 974 doesn't have a clear answer.  chatgpt wrote the words below.   So I'm back to my research.

Can the Repayment Be Treated as Self-Employed Health Insurance?

• No, if your client has to repay some or all of the Premium Tax Credit, the repayment amount does not count as a payment of self-employed health insurance.
• Only the amounts your client directly pays for their health insurance premiums can be considered for the Self-Employed Health Insurance Deduction.

IRS Publication 974 (Premium Tax Credit): This publication details how the Premium Tax Credit works, including repayments for those whose income exceeds 400% of the federal poverty level. The repayment of excess Premium Tax Credits, termed as an “excess advance premium tax credit repayment” (reported on Form 8962), is not considered a payment for health insurance coverage; it is simply the return of an overpaid benefit.

• IRS Instructions for Form 8962 (Premium Tax Credit): Form 8962 is used to reconcile the Premium Tax Credit with advance payments received. The instructions for this form clarify that the repayment amount is an adjustment based on income and subsidy calculations, not a premium payment. The IRS does not categorize this repayment as a health insurance expense.

• IRS Publication 535 (Business Expenses): This publication, which covers self-employed individuals and the Self-Employed Health Insurance Deduction, specifies that only amounts paid for actual health insurance premiums qualify for the deduction. It does not allow for repayments of subsidies (like the excess PTC) as qualifying health insurance premiums. The focus is on direct payments for the insurance policy itself.

• Internal Revenue Code Section 162(l): The statutory basis for the Self-Employed Health Insurance Deduction. Section 162(l) allows deductions for insurance that constitutes medical care, which is defined as the direct cost of health insurance coverage. The law does not include tax credit repayments as part of this definition.