Those numbers are very manipulable and don't translate into real world application for most busineses. Take ours for instance.
I spend almost 800k in advertising, a portion of which is going to direct market our existing database, but the vast majority is in various mediums (network tv, radio, internet, newsprint, tabloids, specialty pubs etc.) If I have say 50k going to current customers and 750k going to outside advertising mediums you could argue that I spent 750k to acquire new customers. If I only aquired 5,000 new customers then you could say my cost to aquirewas 150 per.
I would argue however that I am consistantly pitting out cost effective advertising to trigger response to the whole market, which includes those people already customers so the 60,000+ customers and new customers that use us cost about $13.00 each to get their business this week/month/quarter/year etc..
There are lots of ways to look at numbers and they all have their benefits and potentials for misinterpretation. Do what makes sense for you.
Ken