Well, the updates are often delta updates, which can be different depending on your device and your installation, and I believe that doesn't get determined until the actual moment of you getting the update.That shows the size of the app not the size of the update
They do tell you on the purchase page when u download.. and on the left when side in "Featured" in the description left side (Attached)
It seems pretty accurate to me. When an app says it's a 1GB update, normally it takes a significant amount of time compared to everything else. iOS apps generally update a lot more than just one file. iOS practically reinstalls the app every time. It's weird how it works, but at least it works.
Weird. Fallout shelter says about 1GB each time and it usually takes as long as a 1GB download takes. Guess I'll do some looking and see what is really going on.The app size listed in the update pane is the full installer and not the delta. Real Racing updates every 6 weeks and the app in the update always says 800-900MB, in reality the update is no more than 100MB. I'm able to see this via router logs.
Just curious why do you care? Data limits concern?