Using rental income for mortgage app

[Robert Hastings]

If you have a unit that rents for 500/month and from that unit you cash flow only 150 monthly and you have over two years documented income on tax returns, you will only be allowed to use 75% of that "cash flow" income for a mortgage app??

I have a rental and I have had it for over two years but I have a modest salary and I plan to purchase a home in a year or two from now so I would love to use my rental income to qualify my mortgage. I'm aware that in the mortgage world 150/month in extra qualifying income on a 30yr note  might only amount to an additional 25k in purchase power, where 500/month might allow for an additional 100k in purchase power. 

Thoughts??