But I reckon the poster infers that with less width and the same volume, thickness has likely gone up. I've asked Tiesda to comment, but I know he's super busy at the moment. I have not tried the boards myself so I can't really say. But from a general perspective, it's always a compromise between many factors when designing a board. I'm personally a fan if the feel a thin and very flat decked boards provides. but on some boards I have designed and have instead "been forced to" go for a bit more thickness and slighty more deck roundness to arrive at a matter compromise overall (ie a better "fit" for what the boards is designed to do).
I'm sure similar considerations has been involeved when designing the '11 Kode 94.
And by the way, increasing/decreasing width affects volume much less than you might think. On a fairly big board like the Kode 94, 2cm of width change (some of which also more reflect a redistribution of surface rather than a "pure" width decrease) can be counteracted by only a very marginal adjustment of profile. In fact, you can easily regain that the volume "lost" by just redesign the rails a bit and still keep center thickness nice and low.