[theIV]

I'm not super familiar with this aspect, so this could be totally off-base: because this is sort of "out-of-band" income, it might factor into what you should be paying, but you won't be penalized for it; you didn't know exactly what the estimated income was (i don't believe you have to get a 3921 immediately upon exercise) so you can't necessarily estimate the taxes owed. This could be totally wrong? Also, I think there's a lookback period of a year that you can base your estimated taxes on.

All of this to say, I think what you're saying is a much more precise way of saying what I was trying to get at. :)