there are 3 major credit score reporting agents. throw out your highest credit score and your lowest credit score. the middle score is what you left with and this is the score mortgage reps will use to help qualify your for a loan.
When we use a Tri-Merge credit report with scoring from all three credit bureaus, then we use the middle of the three credit scores for qualifying purposes. For example, a Tri-Merge report indicates scores of 678, 669 and 661. 669 is the middle or qualifying score in this example.
Your lender should be able to explain this better, but my understanding is that you'll have three different scores from the three different credit reporting agencies. The middle score is exactly that -- the middle of the three. It's like tossing out the highest and lowest scores and basing their decision on the middle score only. Make sense?