Consistency in mass produced foods

I was eating a potato chip today from the same brand I always buy. I couldn’t help but notice they tasted especially crisp and fresh today. They always tend to taste slightly different from one batch to the next. With something as simple as potato chips I would think the age of the oil would be the largest contributing factor to inconsistencies.

What would be the best method of managing the oil for consistency? Change every so many batches giving a slight range of acceptable consistency or add a specific amount of new oil after each batch establishing a kind of half life? Some of the oil would continue getting older and older with this method.

I would assume they are filtering the oil frequently, through a very fine filter, and maybe even rendering it themselves when it gets dirty enough. The time the final product sits on the shelf may be a bigger factor in the different flavor you notice from package to package. I recall Frito-Lay used to leave their products on the shelf for no more than 48 hours or something like that, but I get the impression things don’t work that way anymore.