Estimated tax underpayment penalty

This is probably a simple question, but here goes: Are there situations in which you pay more than last year's taxes in total withholding+est tax, but would still have to pay a penalty?

From Form 2210, it seem like if "the total of your withholding and timely estimated tax payments" is at least 100% of last year's total tax, then there will not be a penalty (regardless of this year's tax liability).

What if there was a very large taxable event in the 2nd est tax pay period (a large Roth conversion)? I would imagine the IRS would "want" est tax on that to be paid for the 2nd pay period. But is it required? If I took last year's total tax, divided by 4, and made sure withholding+est tax was at least that amount every pay period, could I just make a very large payment with my 2026 tax filing?

This seems almost too good to be true, but looking through pub 550 and instructions for form 2210, I'm not seeing any issues with this. Those are some pretty dense publications though, so I may very well be missing something.