If you haven't noticed, homeowner's with second mortgage financing are again being taken advantage of!

Example - Home value of $300,000 and you have $300,000  in mortgage debt.  If you have one loan for $300,000,  you will get a rate that is 1/2 - 3/4% lower than if your first mortgage was only $285,000 and your second mortgage was $15,000.  Same borrower, same collateral property, same credit scores, same closing costs yet the lower loan (and I would argue lower risk loan) is assessed an interest rate that is 1/2 - 3/4% higher.   In fact, if the rate selected for the larger loan ($300,000) was 5% then the larger loan payment of $1610 would be higher than for the lower loan ($285,000) payment of $1618 @5.5% or $1663 @ 5.75% without any costs for the second mortgage.

What am I missing?  I would expect that the lower risk lloan would have the lower interest rate not the other way around.  Is this bait and switch or are is this another way to tax those with second mortgages because the lenders that are on the hook for second mortgage products need more money to bail them out?

Have a nice day!