Unfortunately, truckbad, I don't have your answers, but
I would like to add an adjunct to your question:

What if my AGI in 1998 is below 100K but in 1999, 2000,
or 2001 is *above* 100K. Does this matter, or is it only
the 1998 (or year of the rollover) AGI that matters.
Also, what happens if my AGI *is* over 100K? Penalties,
I imagine? Or death by IRS firing squad, perhaps?