For an individual, it’s a detail. At scale, real money.

With 150 million tax payers, if they had a $10 cut off everyone underpaid, that’s a potential loss of $1.5 billion, over half of the annual national parks budget. Not so weird.

I've had something similar happen with MD state taxes. They know all your reported sources of income and know exactly what you've paid, and if the arithmetic doesn't add up, their software will come after you even for small amounts. In my case I had accidentally attributed a small amount in January quarterly estimated taxes to the wrong year.

I'll be quite happy to pay them $11. :) Here's hoping that's all it would end up being.