As such I operated the entire year under the assumption that I have had in the past with properties that I just add up my expenses and income at the end of the year and my adjusted gross (usually very little if I use all my qualifying write offs) and pay the tax on the adjusted gross income.  

The ASSUMPTION that there are no deals to be had on the MLS/Loopnet/Craigslist etc leads many people not to look at them, this is a mistake if you are serious. 

This is not an "assumption". 

My assumption was that it was similar to firing out offers and dealing with sellers.

Just look back to 2007 and you can see how tragic that assumption was to thousands of people.  

I left me corporate job to dive 100% in to the wholesale / loan assumption part of the business and loving it.

I don't want to make any assumptions about what you mean, so maybe you can share more specifically.The above bullets are my view on what drives a healthy long term outlook. 

Don't make negative assumptions. 

Owner occupied triplex and fourplex mortgages historically have higher default rates since folks historically budgeted with overly generous assumptions for rental income in mind, paired with FHA loans allowing for very high debt-to-income ratios (>50%... with the rental income counting -- think about that!).

Loan assumptions are not a quick thing either and you will need a strong sponsor.