Help !!! When Quest app with (apk + obb) is given an update, it is downloading the whole app again.

I had developed a quest app using Unity that has an apk size of 100 MB and obb file size of 1.5 GB. I had got it published on App Lab. When I make some enhancements, add new features, and release an update to users, the users are being asked to download the complete 1.6 GB again.

To upload the app, I am using ovr-platform-util and the command is 

ovr-platform-util upload-quest-build --app_id <ID>  --app_secret <App-Secret> --apk <path/to/Your.apk> --obb <path/to/Your.obb> --channel <ReleaseChannel> --notes <ReleaseNotes>  

When I run this command, I see logs like
"Downloading previous build...."
"Generating patch..." 

Please let me know, how users get to download just the patch (Update), instead of the whole app getting downloaded again.