I am also in the large button, small flush gang. I assume it's that way so the flush you use most frequently is bigger, but it does seem counterintuitive.

Pure anarchy.

From my experience, the large button does the flush, but the size of the flush depends on how far you push it down. The small one simply pulls the large flush button down with it, but stops it from going more than half-way, resulting in a smaller flush.

Small flushes are more common, so it makes some sense to make that button larger.

I think your button had been rotated