I always buy KFC when they run promotions like 24 nuggets for $10, or $4.95 fill up box.
I also always get the free chips and drink with the survey.
Every time, without fail, the chips are poorly filled.
The box may look full because there is one or two chips sticking out of the top. However, if you shake the box a bit, it's easy to come up with extra space. It's very easy to have blank air between chips. I would say that in every case, I could have added at least an extra 30% by mass/volume.
They should tell them to scoop once, and then shake the box for a few seconds to remove air, and then scoop again. It only adds 2 seconds to the serve time. But I guess the problem is not the service time, it's the ingredients they don't want to give away.
I used to work at a McDonalds making burgers, and some of the managers would be cheap and tell us to 'put on less sauce' or 'put on 2 slices of chesse on the double quarter pounder instead of 3' to save cost of ingredients, but I always sided with the customer (and if anything, gave away larger amounts when I was told by a manager to be cheap).
I realise that you are not going to get what the picture shows, but you can get pretty close.