Is there an explanation for these mortgage results?

I just used a mortgage calculator provided online by a real estate firm in the Midwest to come up with the following for three different (theoretical) down payment amounts Price (In the neighborhood of ) $ 489,000 Down Payment $ 400/4000/40,000 Interest Rate 4% Mortgage Term 30 years Payment $ 2, 338 / 2, 320 [...] http://bit.ly/pgv6nP