The rates on the front page of myFICO.com are not advertised rates, they aren't even accurate in my opinion... they really shouldn't even be there as rates are determined by a lot more than just the credit score, so it's more of a selling point to get your FICO's higher, which isn't a bad thing, but it should say that scores aren't the whole picture when determining your interest rate. I wouldn't base choosing your financing source on advertised rates on a website, it's likely going to be the biggest investment in your life, so you should choose your financing source based on the rates/terms, the character of the individual you are working with, and how they will handle the processing of your mortgage.
On 1-unit properties, loan amounts $417k & under are called conforming loan amounts, since they conform to the GSE (government sponsored entity) underwriting guidelines of Fannie Mae & Freddie Mac. Loan amounts over $417k are considered non-conforming, and thus have a higher interest rate.
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