how much "churn" do they have?  

If you just churn out 10 offers 30% below asking, with no apparent strategy, no one is going to take you seriously.I consider a lowball offer to be 25% or more below fair market value in present condition.

It's a churn at least in Chicago

When you do it right, you get your seed money coming back to you too, but the investment is still yours...churning out those returns, over and over again.This way, if you spend these returns on your personal debt, the impact of your seed money can be limitless since the returns allow you to pay off more than one debt...and after all of your debt is paid off, it keeps coming.Think like a REI and not a Homeowner.  

The tenants tend to move at a higher pace and in turn creates higher velocity of churn in an apartment building.

The job is to churn inventory and pass it off as a deal to a buyer.

This of course means you must buy the note at a sizable discount with enough margin to negotiate, if that is indeed what a note buyer is hoping to do.In reality, many note buyers are not wanting to modify, they want to churn the transaction via short-payoffs, short-sales, cash for keys/deed-in-lieu, refi, or worst case scenario- foreclose.

Churn too many notes, moving in and out of holding the note can be a brokerage activity again. 

Just churn out a set of documents and give you a congratulatory pat on the back?

They tend to be much more unstable in the income department and you churn those units more and properties get wore down faster.