Bicycle carrier (AHK) not allowed for 4 bicycles?!

I have just noticed that according to the operating instructions only a bicycle carrier designed for a maximum of 3 bicycles can be mounted on the AHK. Furthermore, the actual support load should not be adhered to here, but the carrier incl. wheels can be up to 75 kg heavy. This obviously applies not only to the v90 but also to the XC90; probably for all models. I am particularly surprised because Volvo itself offers carriers for up to four bicycles as accessories. Does anyone have experience, background knowledge or has been using a carrier with 4 bicycles for a long time? I thank Eich for your feedback!