Ask how to calculate estimated earnings

How to calculate the earnings estimate: 1. If the initial situation does not hold currency, the estimated earnings = end-term balance + end-term balance of currency in the final market settlement earnings-procedure fees-initial balance; this estimate is not a problem. 2. What if there is a holding in the initial situation? What should be the estimated earnings? Estimated earnings = end-of-term balance + end-of-term balance earnings at the end of the market break-even - fees - ((Initial balance + initial balance earnings at the beginning of the market break-even)??)

Please point out to me if the initial situation is holding currency, what should be the estimated earnings?