REIT accounting - COGS and margin

[Robert Mayo]

Hi. I'm trying to compare some of the private deals mentioned here with public REITs.

Looking up the income statements for Equity Residential (trades as EQR) I find a line for cost-of-goods-sold. What is this for a REIT? Is it the cost of maintaining the apartments, everything from the salary of the building manager to the cost of the new bathroom fan? What is under SG&A? Is it the sales reps, accounting department, etc?

I also see margins of 8% to 25% on public REITs (whats left over after deducting expenses from rent). For private deals mentioned elsewhere on the site, people are using a 50% rule -- expenses are 50% of rent. For these public REITs it is more like 80%. Why is this? Is an individual investor that much more efficient than a giant like Equity Residential?

Am I comparing the right things, or have I messed up somehow?