TurboTax cannot do that automatically.
I do exactly the same since the amount deductible for self-employed health insurance will never be taxed while the amount deducted for 401(k) contributions is only tax-deferred. You yourself will need to subtract your self-employed health insurance premiums and the deductible portion of self-employment tax from your net profit and contribute only what remains of the net profit. You won't be able to use the Maximize box to calculate this.
If your 401(k) plan supports Roth contributions, you could use the same compensation for which you receive the self-employed health insurance deduction to make a Roth contribution to the 401(k).
You might also consider contributing to an IRA an amount equal to the self-employed health insurance or the annual IRA contribution limit, whichever is less. The same compensation for which you get the self-employed health insurance deduction will support an IRA contribution. MAGI will determine how much you are eligible to contribute to a Roth IRA or how much of a traditional IRA contribution might be deductible.
