Why do the old and new APK diffs not add up?

Question

I'm trying to reduce the size of an APK and I made the R8 minimization more aggressive by

• Using the proguard-android-optimize.txt file instead of the regular
• Removing the contents of local proguard-rules.pro file to reduce exceptions

The build succeeded and I analyzed the APK using Android Studio's tool. I have attached a screenshot of the output. I don't understand why the old and new size only differ by 0.2 MB when the sum of the "Diff Size" column is around -2.2 MB.

Could somebody please help me understand the image?