Pleasure.

Here's an example to help illustrate:

    Discounted (future) revenues: $100
    Discounted (future) ongoing costs: $20
    Value: $80 ($100 - $20)
    Acquisition cost: $60 (e.g. adwords)
    Net Present Value (NPV): $20 ($80 - $60)

An NPV of $20 means you create $20 in value by acquiring a customer. That's what you were trying to say with "true" value / net gain or loss - but there's no such thing as "true" value - you're either working with value or you're not.

Note that revenue to date did not figure into any of the above - we're concerned with the future here, so the past is only useful in as much as it helps you with forecasting.

The wikipedia page on CLV is surprisingly good, have a look.