Jagman - the author is quoting averages, citing that the market is too fragmented to deal with the broad range of rates.  You should be very happy to have the rate that you do.

Very interesting that the lower ratio mortgage costs more. Intuitively, you would think it is a lower risk and you would get a better rate.  But the coverage of the higher ratio mortgage with insurance makes the high ratio mortgage less risk for the bank and it costs them less to issue (risk based capital).