Former (and recovering) fast-food manager speaking, Wendy’s division. Left fast food management in 1992 and have not been stressed by any job since.
I worked about about half a dozen stories in a 50-mile radius from home, and all of them worked more or less the same: a photoelectric eye simply read whether there was a car parked immediately outside the window, when it pulled up, and how long it (the car, not the window) stayed.
The photoelectric eye could be cheated easily if a drive-through attendant had long arms, a good grip on something heavy (such as a cash register) and a large, flat, opaque object (such as a food tray) to cover the eye with. Not that I ever did that.
A clock by the window gave average service times for the periods of 11-2, 2-5, 5-8, and 8-11. However, the clock we initially had did not give car counts or Time At Menuboard.
Then new clocks were installed, which were tied to the menuboard, to the order count at the register (to compare to actual number of cars at window), and to the menu speaker (to count how long it took to greet an incoming car, and how long it took to take that car’s order). It was much easier to tell if the car count varied widely from the order count (i.e., the drive-through cashier was cheating the photoelectric eye).
Generally speaking, I as a manager didn’t give a rat’s patootie about how long it took to take a customer’s order, because there was very little anybody could do to speed up that process if the customer wanted time to be slow. Service times were a priority for a few weeks after the district manager inevitably said they weren’t good enough, until it again became clear that customers were deliberately trying to thwart us. Cars stalled while sitting on the timer, driving service times up to 999 seconds and pinning the needle, so to speak; customers talked on the phone, added orders on at the window, bypassed the menu so they could order face-to-face, friends stopped by to chat with the cashier, got out of their car to look under the window for the dimes they dropped, checked their order and handed out the correct kid toys to the correct children, finished their beers, etc.
So… service times are a thing which people in very serious suits in offices far away think about, as if they can measure money in seconds, while people who actually have to work at the damn place realize that customers can never and will never give a shit as long as they get their food a) right b) fast and c) tasty, or as tasty as possible under the circumstances.
At least when I worked as a manager, we were not permitted by The Rules to give the cashiers the autonomy to give out free fries, coupons, drinks, or anything else at will for orders which had to be pulled ahead for any reason. For the most part, based on the average age and experience of the workforce, I agree with the policy. There are simply not enough managers on-shift to personally give compensatory gifts to any and every customer who feels slightly inconvenienced. (Add to this that the food cost of the coupon came out of my store’s P&L statement, even if they redeemed it at the Wendy’s across town, so we were not even budgeted for this kind of largesse.)