Are you aware that FreeCreditReport.com is a subsidary of Experian, and the score they report is actually their Experian "Plus Score". It is NOT your FICO score. Your true FICO score will be different than your "Plus Score".
The Credit bureaus have created their own formulas for creating their own "Credit Score", but it's reported that 90% of all banks use FICO scores, which is based on the formula developed in 1956 by Fair Issac.
FICO scores are actually calculated on information received from all three credit bureaus and is based on it's own formula, not the bureau's formulas.
Monitoring your score is an excellent thing to do. So many do not. But instead of using FreeCreditReport.com, I'd recommend you go to MyFICO.com and check out their packages. You can sign up for one of their 'free' trial run packages, and at least get your true FICO score and their report. To get it 'free' you have to cancel within 30 days or else they'll charge your CC. I think FreeCreditReport.com is the same.
I found some useful information on MSN Money:
http://moneycentral.msn.com/content/Banking/Yourcreditrating/P136689.asp
You can also Google FICO and you'l find lots of information.
Hope you find this information useful. Whether to purchase DVC or not is of course your decision and I'm sure you'll weigh everything before making your final decision.