(WIP) I made a way to see blocks built and destroyed in custom areas

Sort of a follow up to my custom shader post (https://www.reddit.com/r/feedthebeast/comments/1szqzp4/i\_made\_a\_way\_to\_apply\_shaders\_to\_customized/) –

I'm creating a mod to encourage building, using customizable "commissions" in game.
I've made a way to see what exactly changed before and after you build in an area, by comparing the contents of the area now to when the world was generated. Right now it's stored as NBT data, but I plan to utilize this later for the full mod.
This works (per my testing) on very large areas (Say, 10 boxes spanning 8 chunks in all directions each), unloaded chunks, and even modifications on existing structures, such as villages or monuments, all processed asynchronously.
The idea is to get a calculation of how much effort has gone into building something.
This is very much WIP (which you can guess from the textures), and I'm sure there's still a lot of bugs and kinks to iron out.
I would love to get any suggestions and answer any questions, especially since the last post was extremely helpful and y'all gave me a lot of great advice. Thanks!