If they required you to put down 7 MSDs to get 0.00245, it means they are actually charging you 0.00294 before the MSDs, which translates to 7% interest rate.
The 0.00180 rate one could get is before MSDs, and after 7 MSDs it is possible to go down to 0.00131.
Now back to your aunt situation. It is what it is. They have looked at her credit and said she does not qualify. They are required to disclose your aunt's credit score if they ran her credit, so check it out. It is probably not as high as you think it is, and her lack of credit history does not make things better. This is America, having no debt and no credit history does not make you a potential good borrower, unfortunately.