There are some lenders out there still lending on lower scores. But they may require a larger down payment.
And as far as your credit score difference? I have seen as much as 100 point difference. That is because there are three different modules that credit scores are determined on. One is the consumer aspect (credit cards), which is the one you get online, auto loans, and mortgage loans. They all 3 have different things that are more important then the others. So you could possibly have different scores on all 3.
Just work on establishing your credit, lower your balances, and pay on time and your score will rise. Don't close any accounts or open any more unless you don't have at least 3 tradelines. Be sure to keep copies of your rent payment cancelled checks or bank statements to show timely rent payments.
Hope this helps!