But here's the real conundrum here, and no one has been able to ever explain it to my satisfaction.'

@Dan DeGroff - I think you can probably do this as a primary residence since the scenario makes sense (e.g. you travel to Aspen for work during ski season), however, there are some major red flags here that you will need to explain and support during underwriting (e.g.

But that set aside, my point is not to define shortage (it is what it is, lack of supply), rather to explain WHY it exists.

Explain the situation and see if they’re willing to extend terms or provide additional funds to complete the renovation.

You need to understand what that means and I always explain that to tenants especially unmarried ones. 

It is possible in theory, as Account Closed explained, but is very complicated and thus expensive to implement.

If you'd like to know more, send me message and I can explain.

Can you explain what the designations Sale and Non-Sale mean?

(b)A person selling or offering to sell an option or assigning or offering to assign an interest in a contract to purchase real property without disclosing the nature of that interest to a potential buyer is engaging in real estate brokerage.Again, using the above example, I must explain to the owner what I am going to do, i.e. purchase the right to complete the purchase of their home on my own, or assign that right to someone else for a fee. 

An insurance broker explained this to me in the past as the law of  large numbers which suggests if a a carrier has significant enough exposure in a market the probability of claims arising will be more consistent with probabilities calculated in their underwriting than a when a smaller sample size were to exist.