Why do I need more than 200 megabytes of disk space to install an APK? I started to get not enough space errors when updating or installing APKs, but I have 200 megabytes of free space on my internal storage, 2,68 gigabytes on my internal sdcard, and 3,62 gigabytes on my external sdcard. I can't imagine what could use more storage than 200 megabytes in the process of installing a 4 megabytes APK. I'm constantly deleting apps, moving them to sdcard, but I only end up having less and less space remaining. How does this work? I want to understand the inner mechanism of how storage is handled when installing APKs, or in situations that can affect it, so maybe I could write an app to help this procedure.

Edit: I'm using BAM Android on a Samsung Galaxy S2 (i9100).
internal memory space is required to store app data and cache, it doesn't matter much if you move your apps to sdcard app data and cache still gonna be in internal memory.
this problem can be solved by rooting.
if not willing then try some apps playstore which delete cache and auto move apps to sdcard