Going to the next level the difference in rate of return from appreciation at 80% LTV vs 0% LTV is 5x.  

Most cost segregation study firms operate at a national level where they will send a professional to your property to generate the report.

It all comes down to what your comfort level is. 

There is a level of participate required when you buy a business and a piece of property.While it always depends, on average, acquiring a business will normally require more work.

It's understandable that you're frustrated and disappointed with the level of service you've received, especially considering the financial impact it has had on you.It sounds like you've made several attempts to reach out to the company, including contacting the VP, but have not received a response.

In our case, this seems to be the best price in town and I trust this AC company so I am happy to pay their price (especially since it is the lowest quote I found).

However, local realtors are saying that rates have come down below 6% Yeah, all trust in this guy is lost. 

Building a solid team is a smart priority, as real estate investing is much more efficient when you have a trusted group of professionals→ agents, contractors, lenders, who understand your goals and the local market.Your plan to own four long-term rentals in the next four years is both realistic and attainable, especially with the type of property you're targeting.

The lower rates then meant that there could be some level of positive cash flow. 

It also appears you can appeal to the Rent Leveling Board.It would be worth your time to speak with the Board or an attorney to see what your options are.