On my iPhone 6s Plus running iOS 10, the Clash Royale game app takes up 800 MB of space, but on my iPad mini 2 running iOS 12, it takes up only 190 MB.
The Clash Royale account on my iPhone is the same as on the iPad, so it has the same data in both, and I usually play it more on the iPad than on the iPhone. How come it takes more storage on my iPhone? Is it because my phone is running iOS 10?