What if it was counted because the teacher thought making the deal was where they made the money, not in the classroom. They made their money in the 2 hours, but delivered their service afterwards, which doesn't contradict her guideline.
So, the income can be counted before obligations are resolved? Tradesmen can "earn" large amounts of money in short periods of time under this definition, as they're often paid half up-front to fund materials, but they still need to do work in order to "earn" that money.
Well it depends on the method of accounting you're business would need or want to use, but in a monetary sense, then yes, it can be counted as cash made as soon as the money, not the product, is delivered.
