Weird to see they are not using a separate texture for AO. The post-process AO works well but most of the times you need a texture for micro-occlusion for small cracks. Some games combines the ao mask with the diffuse map but I really don't like this method (you save memory space but it's not good for PBR workflow).
@Norbyte if you want update the thread for DOS2 standards I'm willing to help if needed.
I'll continue checking things. Thanks for posting guys!