Have typically paid quarterly estimated payments. Increased withholdings this past year to minimize amount owed. Is it safe to not pay quarterly estimates now? Do not want to face any penalties.

Having enough tax withheld or making quarterly estimated tax payments during the year can help you avoid problems at tax time. Taxes are pay-as-you-go. This means that you need to pay most of your tax during the year, as you receive income, rather than paying at the end of the year.

"The safest option to avoid an underpayment penalty is to aim for "100 percent of your previous year's taxes." If your previous year's adjusted gross income was more than $150,000 (or $75,000 for those who are married and filing separate returns last year), you will have to pay in 110 percent of your previous year's taxes to satisfy the "safe-harbor" requirement. If you satisfy this test, you won't have to pay an estimated tax penalty, no matter how much tax you owe with your tax return.

If you expect your income this year to be less than last year and you don't want to pay more taxes than you think you will owe at year end, you can choose to pay 90 percent of your current year tax bill. If the total of your estimated payments and withholding add up to less than 90 percent of what you owe, you may face an underpayment penalty. So you may want to avoid cutting your payments too close to the 90 percent mark to give yourself a safety net.

If you expect your income this year to be more than your income last year and you don't want to end up owing any taxes when you file your return, then make enough estimated tax payments to pay 100 percent of your current year income tax liability."

For more information, please read this TurboTax Help article: Estimated Taxes: How to Determine What to Pay and When

Does TurboTax automatically calculate the estimated payments?  The figures on the generated vouchers just don't seem to add up.