Sorry about that - I thought it was clear from the context of those off-the-cuff estimations that it was 6666 numbers (since that was based off of how many numbers you could scan, not users).
We've added some clarification just to be sure, thanks.
Just checked and you still have this completely broken paragraph:
"Given user_base = 8,000,000, and a numbers crunchable per minute (ncpm) of approximately 6666, we can assume that it would take approximately 20 hours for one $10 virtual server to eat through and find every user's phone number (hours = user_base / (ncpm*60)). At our worst case of ncpm = 5000, it would take approximately 26.6 hours."
Look at it this way: If they only had 5000 users, would you estimate the time to find all their phone numbers at 1 minute? No.
