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If you need your score in the next couple months for something than I would pull reports (reports not just scores) for all 3 bureaus and see what's on all of them and compare. I do this every few months just for good measure.
If you don't need your scores for anything then perhaps give it a couple months from your new account for the dust to settle, then check your free scores again.
go to freecreditreport.com and download all three of your credit reports: Experian, Equifax, and Transunion. If your scores are, in fact, different, then there will most likely be different information reporting to each.
It's the creditors' perogative whether or not to report and to which bureaus to report. Each creditor uses different credut bureaus to inquire about your credit as well.
Keep reading. You'll find everything you'll ever want to know on the myFico forums!
Good luck!