When you are shopping for a mortgage it is important to know what you are looking at when it comes to interest rates and fees.
The Truth in Lending Act requires lenders to disclose the APR for any given loan they offer. The APR factors in the total cost of borrowing from that lender; this includes the interest rate and all fees charged by the lender. When shopping for a mortgage it is important to compare apples to apples by using this APR.
Using any other factor does not give an overall comparison of the mortgage, like comparing an apple to an orange.