In the grand scheme of things, it’s not using much more. And if the prices are correct in OP, the markup on the new can is way higher than any extra cost they are incurring from additional raw materials. They probably had some marketing study show that a taller looking can makes consumer’s less angry about a price increase or some other crazy nonsense.
Force inside a cylinder vessel is just pressure times surface area. If you have the same pressure(soda carbonation) with more surface area, then you are putting less force on the walls. I don’t have any specialty in the materials engineering for canning, but i suppose less force on the walls means you could use thinner materials. However, soda can walls are already pretty thin to start with and from what I can find online, the tops are usually 2.5-3 times thicker. So, I could see it potentially cutting some cost from the tops by making them thinner but i doubt they are manufacturing different tops. It’s probably just marketing.