It seems like all of my friends kept their cell numbers when they moved to the valley. This means you have east coast phone numbers with a west coast human behind it. The three hour difference can be a big deal if someone guesses incorrectly.
I don't know how to help you get better location info given a number alone, unfortunately. Sorry.
I'm from the UK, so I often forget that:
a) cell phones have area codes (unlike the UK),
b) area codes do not change when cell phones move, and
c) there's no way to tell a cell number from a land line number (again, unlike the UK).
Put those three factors together and you're right - the tool becomes far less useful for cell phone numbers.
I'll do a bit more investigation and see if there's a way to improve this situation. Thanks for the input!
I don't know how to help you get better location info given a number alone, unfortunately. Sorry.