Buttoning leather is a different craft from buttoning cloth, and the difference is that hide does not gather.
Cloth can be eased into a pleat with the fingers and will take up fullness. Leather will not - it is a skin, it has no give across its width, and any attempt to gather it produces a hard crease rather than a soft fold. So on a buttoned leather back, every pleat has to be cut for rather than gathered in: the hide is marked out and slit at each button position, and the fold is formed deliberately and worked flat.
Our upholsterers also work from the centre button outward on leather, never from the edges in. Cloth can be re-tensioned after the fact; leather cannot, because the button holes are already cut. Start at the outside and any accumulated error is trapped in the middle of the panel with nowhere to go.
The hide is also chosen with the buttoning in mind - a thicker hide holds a crisper fold and a thinner one drapes more softly - so we ask what look you want before selecting the skin rather than after.