Hopefully I can make this clear with an example. On my current keyboard, Alt is directly under X and Win is directly under Z. On most of the models of mechanical keyboards I have looked at, those keys are shifted well to the left of where I am used to. The bottom row layout is often (3 keys, spacebar, 4 keys). If I could switch it to (4 keys, spacebar, 3 keys), that would match what I am used to.