It's not just for enhanced rate either. A fair few people on Lower, Middle and Top rates are affected too. I asked this question months ago with very little response. Having been on my current rate for two and a half years, according to the list I won't be seeing the next rate until 2012, when the system says I'll have "come into line".
I was never meant to be a rich man, but I'm sure someone waits for me to get to the six yard box before moving the goal posts! Anyway, back to living the dream.
Have a nice day out there PPruners,
RotP