@Melody Kushi Seems like you have enough answers, but yes, listing agents will do their homework and they should.

Math is math.

I asked a pretty broad question and ended up with some broad answers, but I think everyone is basically getting at "if the math works out, then it's a good deal."

If we're scaling that concept and using a 2nd property with the same exact figures, your DTI% would stays the same, since that ratio hasn't actually changed - is my math on that right?

Math is telling you to buy more houses with leverage.

Fix it up using my experience in such matters from working in my families live-in shoestring budget 5plex from my younger days and rent it... using the rough and inaccurate "napkin math" of rental prices vs average mortgage cost of the listing price, most are worth taking a closer at look to see if they make sense at the micro level.

now back out 600 for rent back out 200 for utls cable etc. back that leaves your tenant with 1000 a month before any tax's taken out.. to pay for car  gas  insurance clothing food kiddos dog dog food.etc etc.. you can see why the 600 dollar renter by and large is one flat tire from missing rent.. or say Christmas comes around.. now lets take the 1200 dollar renter run the same math.. 3X  3600 a month to qualify.. 1400 for rent and utls. leaves 2,200 a month to live on etc.. or double the stability.. this is why the risk is so high.. 

Do you your homework and speak to professionals in the area where you are renting and read the articles by Scott Smith.

You're certainly doing your homework and asking the right questions!

Do the math.