How does selling a property with a wraparound mortgage affect DTI

[David Verde]

Ok, scenario - I own a house with a conventional fixed-rate mortgage at 3.5% rate.  For simplicity, lets just say I owe 200k on a house.  Now, I want to sell the house to my cousin for 200k using a wraparound mortgage at 4% with no down payment - I'm mostly trying to do this to help out my cousin, not to make profit, so I'm happy with the half point spread.

My question is, if I keep my original mortgage and issue the wraparound to my cousin - how will that affect my debt to income ratio if I go apply for another conventional loan to buy a new house?  Will my existing mortgage still be counted as debt by the mortgage broker?  Will the mortgage payments from my cousin count as income?

I know that with rental properties you only get to count 75% of the rents as income, but with a seller financing wraparound, is that still true?