In other words, do more expensive properties clear a higher dollar per door rate, or do operating expenses scale proportionally (or are repairs and CAPEX so volatile that it is hard to draw the conclusion)?

A prior thread on BiggerPockets suggested using a 20% vacancy rate for offices due to their volatility, but I'm having a hard time making that case to the broker based on the market data available.

However, what I think Minh is getting at and I agree, is that by buying distressed below retail market and then forcing appreciation gives you a margin of safety against any short term market volatility.

That would give you much superior returns over paying a bunch of middle men, you would also then be assured that the rehab was done up to you quality standards, and finally it would hedge your investment to a large degree from any short term pricing volatility caused by a recession or other events outside of your control.

If it is a restaurant, seek a higher security deposit too since the industry can be so volatile. 

They ignore appreciation, rent growth, volatility/risk of the NOI (though they can be used as a good reflection of that), how you have the property financed, any value added to the property, tax implications, etc.

The only way to increase your return is to increase your risk, either by looking into more volatile investments or something that will lock up your money for a period of time (CD, Short term Bonds).

They have a lot of price volatility.

Many lenders are not currently locking rates, due to the current market volatility, because if their cost of capital increases between the time of submission and closing, the lender may be losing money on the loan.

Diversification is Key I have always believed, even more so during times of heightened volatility, that diversity is the key to any successful business or investor strategy.