My cannondale Road Warrior 800 has a Satori Poise XC suspension seat post. However, the unit that allows the seat to rotate about 30 degrees left and right. Is this normal? I thought seats were supposed to be fixed in their alignment with the frame. The rotation happens where the top of the post tube meets the seat clamp. It is not the suspension tube nor is the unit rotating in the frame. any one have experience with this?