They are optional to pay. Turbo Tax is very conservative and doesn't want you to owe too much next year. They might have printed out if you got a one time large income this year. Like if you took a IRA or 401K distribution. You can ignore them. You might want to adjust your withholding at work so you won't owe too much next year.
If you are receiving a refund or low tax due and TurboTax prepared the vouchers then your tax liability was probably reduced by credits.
