While doing some reading on belt positioning (rear facing is below the shoulders), I came across this interesting bit of info.
Maybe you already know this, but I didn't!
The carry handle must be in the correct position, usually either curved around the top of the seat or under the seat.
Many people mistakenly think that the carrying handle will perform as a "roll bar" in a crash, but in reality, most handles are not designed to withstand the force of a crash. Upon impact, the handle can shatter or break, sending sharp, jagged pieces towards baby or other occupants in the car. CHECK THE INSTRUCTIONS. Most seats require the handle to either be around the top of the seat or underneath it. Only a few seats allow the handle to up over the baby during travel.
Re: FYI Carseat
ETA I just looked at the chart and my Britax can be left in any position. Now I don't feel so guilty. Phew!