Correct, but, if you made loss, don't subtract that amount bcos as per your current formula, that will happen.
TO will not include any taxes, brokerage etc.
All the tax, brokerage etc will be added to Business Expense and deducted there against your gross income.
So, in above trx your Income = 750,
less expenses, say. brokerage tax etc = 200
So net profit = 550