If you have a large, one-time increase in income for a tax year, and your income will drop back to normal in the following year, are you nevertheless stuck paying a large estimated tax payment each quarter in the following year?
Or, can you simply increase your withholding to exceed the 90% withholding threshold to place you in safe harbor? (I would opt to adjust my withholding to be well above the 90% tax bill I would estimate to owe for the following year.)
I realize there is a risk of having to pay a large penalty if some unexpected financial windfall magically appears.
