The reason for different scores

Mortgage lenders usually use FICO scores to determine one's ability to pay them back. Since the three credit bureau scores are different, some banks look at all of them to get an average, or tri-merge, score.

Two common factors in determining your creditworthiness are timely payments and credit utilization. Other factors like credit history, types of accounts, and recent hard inquiries are used to varying degrees. It means that the score you see may be different to the score a lender use.