That's not how it works. It's percentage changes that are significant.

Every thing in my cart increases by a penny. It (the cart, my food) now costs $2 more. Easy math. Change that to percentages and amount increases, of course.

They do play with pennies. I worked in a huge national restaurant chain as a teenager and went through numerous menu updates. They were always flipping nickels and pennies all over the place on the menu. As a kid I thought changing the menu prices by five cents was ridiculous. Apparently, that's how it works in this business with razor thin margins.