DTI ratio and having multiple leveraged investment properties

[Account Closed]

I'm curious about how debt to income ratios are calculated- in particular, income from other investment properties. In chess, if you are up a piece, you want to do even trades to water down his men and have a higher percentage difference even though you always have the same absolute difference. 

In RE, the more properties I get, with notes attached, even if they all cash flow, the more my DTI approaches 50% or whatever.

Say I make 100k from my job and only have my home mortgage of 1500/mo and nothing else. That's a good DTI. Say then I buy 5 investment properties with massive amount of debt but each cash flow by 300. Given their formula for vacancies, I can see how they justify modifying these numbers, but given that, do they treat these properties as black boxes and only contribute net income to the equation or do they add both the income and debt sides and penalize the successful investor? 

If they gross both sides up, is there a way to avoid this penalty or bypass this so your DTI doesn't go stale and plateau (because each property is a producer)? 

I'm only starting my research in this but feel free to share your wisdom.