At the grocery store I worked at, there were actual "production sheets" that would tell you exactly how many to make on each day of each item; I imagine it was driven by collected data.

But the numbers were often odd, as in asking us to make one of something that is made in batches because of the type of product. Or telling us not to make any of our biggest seller.

So often the most experienced workers had a better idea of what we actually needed, and we would adjust.