Bryan. I think I understand your initial thoughts in that you are wondering why an investor who you are seeking to buy into your fund is not willing to invest in a solid ongoing return and would rather wait for a home run and make it.
I think that most RE investors are not scientific in their approach. They do what they have done before and nothing else. In the past they have done well with the hit and run and they do not want to deviate from what has served them so well.
Ask many of these investors and they will tell you how a market can tank overnight, things can change at the drop of a dime, etc. They will have a thousand horror stories that you can prove wrong, but it does not matter, it is their experience telling them otherwise and your fancy equations do not matter.
I can bet that the investors that give you these excuses are very conservative and do not want to risk their hard earned capital. I have several friends who I could easily put into fix/flips with substantial returns, even if I am an extra 10%+ of FILO cash, it does not matter, they want a home run or nothing at all. Even if I am taking the extra 10%+ risk. As a result of knowing so many of these types of people I simply have given up raising cash, until recently inspired by Steve L, and rested on my own funds.
As for your reference to the precise equation - no, I do not feel that it would be valuable to a typical investor. It is valuable if you are dealing with traders and speculators like Niederhoffer or the like but these guys are not interested in the few million I could put to use. Traders that understand the equations are too big for what you are doing - or what I assume your are doing. You could put together some equations for larger use, such as with larger scale note purchases, but most of us lack the historical data to substantiate the equation and those that are willing to look at the data are already in place using it with MBS and other securitized instruments.
In the end it is business as usual and if I were filling a fund I would be looking to individuals that do not derive their primary income from RE. or at least those that are only operating at the higher levels of RE and find a 6% cap rate acceptable. Other RE investors are simply too used to making 30%+ on every 120 day deal.