One other note. You've indicated that you are using TurboTax Business. If your solo 401(k) plan is established under a business for which you would use TurboTax Business, the only case I can think of where you would be asking TurboTax to enforce solo 401(k) contribution limits on your individual tax return would be if the business was a partnership with the only partners being spouses and there are no employees. In that case the contributions would have to be present with code R in box 13 of the Schedule K-1 (Form 1065) and that should show only the deductible contributions, not any after-tax contributions (because box 13 is for deductions that are being passed through).
