Set up payment plan in Turbo Tax or On Line?

Correct. Setting up the payment plan as a Direct Debit through TurboTax will save you money. Keep in mind this is not a saving from TurboTax, and we have no affiliation with the IRS, nor do we guarantee this saving. 

What this saving refers to is the set up fee. The IRS charges a payment plan set-up fee. There is a discount set-up fee if you set up the payment plan "online". If you apply by phone, mail or in person the payment plan set-up fee is higher. Some people might qualify to have this fee waived if they fall under the low-income category (if qualify, this is approve by the IRS, not by TurboTax. 

For more information on the different fees, click on the Link below (scroll down to "Long-Term Payment Plan (installment agreement)")

Additional information on payment plans