@k-young-y @VolvoGirl that is correct - you can get a penalty even if you are due a refund!
That is because the assessment is based on (keeping this simple) the tax liability less the refundable credits. If that exceeds $1,000, the taxpayer is subject to underpayment penalties.
Importantly, the estimated tax payments and the April 15 final payment are NOT part of the assessment.
suggest closing reading the flow chart in the link below and form 2210.
https://www.irs.gov/pub/irs-pdf/f2210.pdf
