I wonder whether all GTIs had the 2.4 pressure sticker and ED30s had the 2.6 sticker?
If T_T was lurking round here, he'd pounce right in and say how you can and should adjust the pressures to suit the situation as the stickered pressures are guides only. Certainly if you're luggin a lotta stuff round, I'd smack the pressures up a tad, especially at the rear.
2.4 bar = 34.8 psi
2.6 bar = 37 psi.
There's so little in it, I'd try ramping up the pressure.
Definitely when my car went in for a service a few months back, the pressures were lower than when I'd had the car before. It makes such a huge difference. Try it and see how the car feels. I found improved handling, feedback and mpg.