In terms of your question. To avoid using Excel’s iterative calc feature when dealing with Circular References, Spencer instead uses a Macro to solve for circular logic. Such is the case when solving for loan and equity amounts.
You’ll notice that as you enter inputs, a ‘Recalculate’ button will appear across the top of the screen anytime the model needs to recalculate. By clicking that button, a Macro runs and the value in cell I56 (among others) change.