Yes, and the materials used, the ingredients, pots, and cooking heat, can have much variability, so precise measurements doesn't guarantee uniformity or the desired outcome, however that's defined. Luckily, processed ingredients rather than raw or fresh material, is more homogenous and works better.
Military, fast foods, and cafeteria cooks do it by the numbers or measures, and their cooking has a reputation of its own.
Chefs taste and examine the ingredients purchased to insure it has the characteristics they need, if its less or more than expected, they adjust the recipe as needed, most sample the effects of cooking and adjust in the pot too. So in the end, chef style is tied to the chef's palate, and the recipe is a guide not the law.
I am an engineer, so I understand numbers easier than chef do understand receipes.
Even measuring the same weight with allmost-a-gram precision, there are many other factor which will make a food not exactly a clone of the previous one. In breadmaking, flour can differ, temperature is not the same, when you put "a teaspoon of sugar" some crystals can fall and feed better the yeast in one part of the bread, making it inequal, and so on.
We, technicians and engineers (politically corect!) call this "tolerance"