When you download an app from Google Play sometimes its not clear about how much space it will actually take. Sometimes a very small app will require a 2 GB expansion file and other times the app updates are quite large. Google is going to address this issue and keep app file sizes in check.
Google is developing a new algorithm further compresses the size of apps and updates by a considerable amount. Google has called that “bsdiff” and it will reduce a download by 50% to even 75%. That, of course, depends on how much new data and code is included in the patch but it’s still a substantial amount of savings.
This new coding change will also be applicable to expansion files and Google plans on compressing them an additional 12% to 65% on average.