The seats don't just slide downwards, the seating part slides forward on the frame that is fixed, so in effect the top of the seat gets lower, the angle of the

The seats don't just slide downwards, the seating part slides forward on the frame that is fixed, so in effect the top of the seat gets lower, the angle of the back increases, and the forward edge moves forward. The space under the seat isn't affected. But yeah, the seats are probably bulkier.