Well,
If you reading the back of the booklet, it clearly doesn't say that. You may have misunderstood. It should say: (if this is a National Plan Booklet)
"Cingular reserves the right to terminate your service if less than 50% of your usage over three consecutive billing cycles is on Cingular-Owned systems."
I don't beleive it is on Rollover Minutes too.
chris