Experian uses a different score (which I think that they call the Plus score, but don't quote me on that part). They calculate their score differently, which is why you see the different score. Other CRAs generate and use different scores, which will be different than their respective FICO counterparts.
FWIW, the CRA scores will usually have a disclaimer that says something like "This score is provided by whoever for educational purposes and is not used by lenders to determine creditworthiness".
