It sounds like you may be entering your SEP contribution in the section in TurboTax for Traditional IRAs OR that you haven't yet entered your income and expenses for TurboTax to determine the allowable amount of a SEP contribution.
SEP-IRA contributions are entered in TurboTax after the net profit for the self-employment income is entered in the section "Other Business Situations" (online) or Less Common Business Situations (desktop/installed) and then "Self-employed Retirement."
Please note that by filing your extension, you also extended the time to make this contribution. Therefore, if you determine that a larger contribution would be beneficial you have until October 15, 2020 to make it. You can even file the return with the contribution amount you expect to make by October 15, 2020 to get in motion a refund (if applicable) and use the refund to fund the contribution.
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"
