I believe originaly...that the m118 was designed to combat/compliment the (imo) harsh tinnyness of the CMC4 mic body.
I've not heard that from anyone..but always figured that he built these around the schoeps mic, and that he addressed the sound appropriatly. Adding warmth and punch was a big deal for a cmc4/mk4.
I dont find it so necessary for cmc6 mics though, and find that newer scheops > m148 recordings sound a little "thick" to me.