The variance in percentage has to do with a combination of several factors.  

I've seen how deep they have to go and its gotta take forever by hand.

I have seen some things that have been on there forever, and upon a closer look of the proforma, it seems to be a solid deal.  

Craig, More Factors here than what you have listed, but for a QUICK Evaluation in Self-Storage: 1.  

Location is probably the most important factor of it all.  

With all of these factors coming into play.

Many other factors can influence the ultimate returns these projects generate.  

I am not sure if this is a forever issue once you take advantage of Section 179 or just until the vehicle has been completely depreciated.

@Kodie Altvater costs are ultimately a factor of 2 items, if you're efficient: labor+ materials.the goal is to arrive as close as possible to just those 2 factors with as little add-on as possible. add-on being profit, a companies overhead, etc. labor and materials are unavoidable (as well as other stuff like permits)....so how does one arrive at those costs?

Make sure you factor that into your numbers.