Published: Jun 13, 2013 5:30 PM EDT
Updated: Jun 13, 2013 6:08 PM EDT

FORT MYERS, Fla. - Mark Nagy hoped to refinance his mortgage. He paid almost $200  to the credit bureau Experian, so he could monitor his credit score regularly.

When his score reached the mid 700s, he felt confident he would get the best mortgage terms. But that didn't happen.

"During my call with the bank, she proceeded to pull my credit while I was on the phone, and she came back with numbers substantially different than what I had recently checked online, by a difference of 22 points," Nagy said.

Consumer Reports says often the credit score you get is different from the score a lender uses.  It took a close look at FICO, the company that invented credit scoring.

"FICO alone has dozens of different scoring methods. And there are hundreds of others. They can all grade the same credit profile quite differently. So we just don't think it's worth it to buy your credit score," said Margot Gilman with Consumer Reports.

It is important, however, to check your full credit report regularly for possible inaccuracies. You can get your report free every year from each of the three major credit bureaus - Experian, Transunion, and Equifax - by going to annualcreditreport.com.

"When you are applying for a loan, you should always ask to see the actual credit score that the lender is using, and if you think that it is too low, you should ask for them to show you why," Gilman said.

Another tip from Consumer Reports - shop around for the best interest rates because lenders can rate you differently.

As for Mark, he was dismayed that with the credit score the lender used, he didn't qualify for the best interest rate.

"I think I should have access to the same credit score that the banks and the creditors do," Nagy said.

There's currently federal legislation pending which would require lenders to annually disclose for free the actual credit scores they use in assessing loans. But it's not yet law. Meanwhile, if you paid for a credit score that ended up being significantly different than a lender's you approached, consumer reports suggests demanding a refund as you would any defective product.