Not so fast... You can set the deductions as you like, but you're
supposed to pay quarterly once your tax bill exceeds a threshhold (either $500 or $1,000 if I recall correctly). If you don't, but still file and pay at year's end, you're likely to get away with it.
But that's only getting away with it. Maybe. I'm neither a lawyer nor accountant, so YMMV.
Well it's been 30 years and we used a tax accountant, so I assume I'm in the clear. :-)
Then again, I'm a conservative, so that little troll running the IRS may have other thoughts...