TurboTax has nothing to due with the IRS payment installment plan.  If you owe taxes when you file there is an option to select setup a payment installment plan.  There is interest added when you enter into the payment installment agreement.

Why do I owe interest and penalties?

Interest and some penalty charges continue to be added to the amount you owe until the balance is paid in full. Learn more about penalties and interest.

Additional Information on Payment Plans

https://www.irs.gov/payments/payment-plans-installment-agreements#:~:text=A%20payment%20plan%20is%20...