Next Step booster and tether

[HH]

We own a Century Next Step DX, and recently change to the belt positioning booster. I was told by a salesperson that we're NOT suppose to use the tether when it's a booster seat because the seatbelt can't do it's job properly if tethered. This doesn't sound right to me because the seatbelt isn't moving freely when clipped into the belt positioner. I think it's more stable with the tether. Does anyone know about tethering in this situation?

[tobymc]

I'd call Century to confirm this. Some combo seats allow use of the tether while in booster mode, others do not. The way the seat moves in a crash will be different, and some think it helps. I like to use it because the tether will hold the seat somewhat in place if there is no child in it if I forgot to buckle the seat in place.

But you should go with what Century says.