I'm here to provide some insight on your question regarding Simple IRA contributions.
As per instructions from IRS, QuickBooks recognizes Simple IRA as tax-deferred. This means that deducted amounts are exempt from federal and state income tax withholding when processed through payroll.
However, they're still subject to Social Security and Medicare taxes. Amounts withdrawn from this plan, after retirement, are subject to income taxes. Detailed information on this plan is available on the Types of Retirement Plans page on the IRS website.
I hope this response finds you with a smile. Please know that I'm always here to provide help and answer any questions that you may have about IRA contributions and how QuickBooks handles it.