Ive never seen production or custom surfboards follow that pattern through their size range. Some will preserve more width or introduce more hip or whatever as they size down within a range, but I haven't seen a model of board that is wider in its smaller sizes than in its larger sizes.
Just a quick look at any surfboard site like rusty, channel island or firewire and you can see the scaling of width and thickness within a model line scales in the same direction as lenght.
You're correct for "production" surfboards of the same model usually they follow the rule
shorter board = less width and longer board = more width probably assuming that the shorter board is for a lighter guy and the longer board is for a heavier guy.
Sorry but probably I don't explain correctly my question about surfboards...............
When I talk about surfboards I don't specify that I refer to "custom" surfboards (I prefer to buy custom surfboards) for the same person. So if I like a surfboard model and I want
the same model but shorter I would ask the shaper for more width and tickness.
So I was not comparing apples to apples.
Because I was comparing customs surfboards with production kite surfboards