to avoid penalty, compute your Required Annual Payment using the prior year's tax rule.
Each quarter your withholding plus estimated tax paid must be at least 25% of that amount, even if your income is uneven,
You are protected from unplanned jumps in income such as capital gains or bonus.
That won't help you now. Assuming $400 is a lot of money,
it is worth your time and effort to attempt to see if Schedule AI can reduce your penalty
