If its second hand , probably former owner chached tires to a higher load-kind ( fi D to E load) .E load needs higher pressure for the same load then D-load .
So the advices on the sticker somewhere on the car can be for the original tires.
For that reason its better to re-calculate with my Motorhome-tire-pressure-calculator.
In this map download the newest version by RIGHTclicking and then choose Download from the dropdownbox.
If you cant work it out , Give GAWR's and tires maximum load and load-letter or "maximum load xxxx lbs AT yyy psi(cold)" and I will do it for you and procuce a picture of it in my answering post.