Nah it takes at least a week. And actually to REALLY understand it takes up to 2 times the cost of the product per ad. So that could technically shorten it. For your client, I would phrase it rather as smth like: I understand it must be frustrating to wait for results, but if we throw a lot of money against the ads right now, you will lose a lot of money you will not see again. Instead, it's better to wait a week to see which ads win, so we can scale those and maximize your income.