My average wait is 7 minutes. If I go during off peak hours, 8 minutes tends to be the full turn around time. At a busy location, can be as little as 5 but rarely over 8. I may have reported a 11 minute wait once, during a very busy lunch with lots of call-in/web orders going on at the time.
The 15 minutes after is for dining room observations. They assume we are focused on the kitchen and cashier area, which they stress about, while waiting for the order. It is reasonable to assume we would miss required observations if trying to watch everything everywhere in just 15 minutes.
My posts are solely based on my opinions and for my entertainment, contact a professional if you need real advice.
When you get in debt you become a slave. - Andrew Jackson