App updates seem same as app downloads: why?

[MohitKJain]

Hi there, I have a Lumia 1520, and frankly, I love it.
I have large number of apps, especially games, installed on my phone. But, whenever there is an update, the entire app downloads itself. As for example Asphalt 8. Why is it so? I used to have an HTC One X+ and it never had this issue. Can somebody let me know as to why is it so? Thanks in advance.

 

[Laura Knotek]

I don't think it's related to the device you have. These new updates probably are just more substantial updates than the previous ones.

 

[MohitKJain]

But, every single app update downloads the entire app, case in point, recent whatsapp update.