Asstance with default.xex

Hi guys.

Let me start by saying how awesome all of you are by taking the time out of your day to make miracles.

I really hope this is the right place to ask this. I'm very new at decrypting the default.xex (lets use diablo 3). When I follow the procedure to do so with xextool and put the newly encrypted file on my HDD, I get an error saying version mismatch (Also noticed after encrypting and compression the file goes from 16.5 mb to 6 MB?)

if someone could please point me in the right direction so I can do this right.

Thank for taking the time to read my post.