Differences in forehead reconstruction surgeries?

[Myself]

I was wondering what's the difference between Type I, II and III foreheads.
What are the different techniques for each type.
I was told I am "type III" forehead but don't have much bossing.

What does it mean?
Is there difference in result if they just "shave it off" or do the reconstruction technique where they take it out, remodel it and compress/wire it back in?

Or is it just "it improves more because there was more to be done, not because more was done"?

I'd love any information about this procedure