Support load AHK bicycle carrier XC90 T8

Hello together, Have the XC90 T8 MJ2019 with the semi-electric AHK and since the WE a Thule bicycle carrier. The trough allows 60kg load (3 wheels) and weighs even 23kg. According to the vehicle license and manual, the maximum support load of my car is 110kg. In the rear part of the manual, however, the bicycle carrier is described that only a maximum support load is allowed if a bicycle carrier is used. Question: why should the maximum support load be lower when using a bicycle carrier than the one indicated in the vehicle license (= 110kg)? If I put a correct trailer on it then the 110kg support load is allowed again. With full 60kg bicycle load and 23kg self weight of the bicycle carrier, I would be in total already at 83kg, i.e. over the 75kg shown in the manual for bicycle carrier operation. However, the 83kg are still far away from the 110kg allowed in the vehicle license. What (reasonable) reasons should there be that Volvo limits the support load to 75kg here?