Water Profiles - Do they help with calculations?

I have set up a local water profile - does it help me in any way when calculating beer characteristics (especially IBUs due to different hop utilization), etc?

If I want to brew using my tap water, but change the chemistry to emulate a different region, how can I calculate the additives needed?

Great program - I was very pleasantly surprised, after seeing other tools available.  As soon as my beer fund has $$ again, I'll purchase!

Thanks,
PoB

Hi,
  Sorry I missed this one, but no the water profiles do not significantly effect the other calculations.  Hard water, for example, increases the "perceived bitterness" and not actually the IBUs.

Thanks,
Brad