Answer
What is key is to always check the Top Tether is correctly tight. An green indicator on the Top Tether is ensuring the correct tension.
To obtain the best tension of the Top Tether, you should look for the shorter routing, going directly from the top of the car seat to the Top Tether hook (often located on the luggage compartment)
We recommend to remove the headrest to avoid deviate the top tether routing from this shorter route, and consequently ensure a very tight installation in any situations.
Installing the top tether in between the headrest or on top of the headrest can deviate his natural routing, and be less efficient in case of impact.