Is there an order?

I've tried to get some help but haven't yet. I'm wondering if there is an order you have to click on the Diving Shop customers inorder to have EVERY purchase counted? I know you have to follow the arrows to get some orders filled. But is this perhaps why it's not counting all of my intertube or diving tank purchases? It took 23 purchases to fill the requirement of 15. I just don't understand. PLEASE HELP!

If there's an green arrow, the customer is hiring a mask or scuba tank. When you click a green arrow box it will count as a purchase.

When the arrow is orange, the customer is returning the mask or scuba tank. This is when you're paid but it doesn't count as a purchase.

So if you need 15 rentals, only green arrows will count towards that.

I hope that helps