Thats how we work. I know we are different than other companies. With us, our customers are buying to to a programmer and they manage there own tasks and projects. Who knows better what you want than you yourself. The programmers will do the work as it is assigned, and then the customers review the work. You are your own project manager. Of course, this means that the customer is responsible for the outcome of their project. It upt o them to make sure the work is completes and done on time. This is whay the purchase is time based and not task based.
What happens in rare occasions is that a task is assigned that could take full time programming time. We will let you all know when that happens. The programmer will alert our staff and you will be notified. Sometimes things can take an hour, sometimes what seems easy can take many many hours. How would you know if your not a programmer?
So, your arrangement here is for time only, its up to you to manage your tasks and programmer. The customer also needs to check their work to make sure it meets their requirements. Make sure you check your tickets and work progress often, its all up to you.