Cash on Cash Calculation Question

[Julie Hassett]

Hi! Math question here...

As my property cash flows and I build up a reserve of money, does the "money invested" part of the CoC equation change? Or does it always stay constant?

Scenario: I buy a property for cash... $95,000 all in. It rents for $1250 per month. After a few years, I have $25,000 in my bank account that I can either leave there or redeploy elsewhere. 

So, is my CoC return always based on the original $95,000? Or at this point, do I technically only have $70,000 cash invested?

Is the "initial investment" static or rolling? Especially if, at some point, you use your cash flow to buy another property.

I could NOT find this answer anywhere online, so thought someone here might have some insight. Thanks!