Britax says the Boulevard CS covers won't fit a standard Boulevard. Does anyone know why? I thought the only difference in the seats was the clicking buckle? I really want a Cowmooflage cover for my Boulevard, but I don't want to buy a new seat. I keep telling myself that Britax also said Decathlon covers wouldn't fit a FPSVD, but it is the same shell and they absolutely do. So, any insight?