As I said previously:
When determining tyre pressures for gravel, one starts at a pressure that is possibly to LOW, and then work your way up until the ride becomes uncomfortable.
It could be worth your while to find a bad piece of gravel road to experiment.
Load the vehicle the same as you would on a typical holiday trip.
Go up/down (depending on whether you start high or low) in increments of 0.2 bar until you find the correct pressure for your vehicle with load.
I would start at 1.5bar and work my way up in increments of 0.1bar.
The whole family of Pajeros are renowned for their gravel road driving, so your experience is not the norm.
PS On a recent trip, 4ePikanini (in his Gen3) and I in my Touareg did quite a bit of gravel road (good and bad) and he had no problems. I had the Touareg up to 120km/h on some stretches, and Marius followed without complaint.