Printable IN Estimated tax vouchers do not make sense.

[DW47]

Because I will not take RMDs from IRAs income will be lower in 2020. I made the adjustment on the appropriate page. The amount for 100% of 2020 estimated tax was 3,168. The first two vouchers were $640 and I combined them to 1280 in the first voucher. If the 3rd and 4th vouchers were $640 that would match the tax estimate with the 4 estimated payments and withholding from a pension. But... The 3rd and 4th vouchers are $383. This would seem to produce a significant underpayment. There seems to be a problem. I've tried everything I could think of .  I can just write over the amount on the3rd and 4th vouchers before using them but that doesn't solve the turbo tax problem.

[macuser_22]

Yes,  you can put and pay any amount that you want to.  The vouchers are totally optional.

You can also pay online and not use the voucher at all.

https://www.irs.gov/newsroom/heres-how-and-when-to-pay-estimated-taxes