TurboTax offers those vouchers as a "suggestion" for filing estimated tax payments for 2017. TT calculates those payments based on the safe-harbor rule, which ensures that you won't underpay.
If you know that you don't need to submit estimated quarterly tax payments, just disregard those vouchers. More info below:
https://ttlc.intuit.com/replies/3301872
*** I am NOT a tax expert. I am a seasoned TurboTax user, and volunteer to provide assistance to TT users. Nothing I post is to be considered TAX ADVICE; I bear no legal liability for responses.***
