It really depends upon the slope. However, if I am using the ramp to level the van side to side on level ground, I now try to go forward onto the ramp, not to reverse onto it. The reason for this is not high-tech. We did an overnight on a French site en route to Spain in the winter and left before dawn. Having reversed onto the ramp, there was not thump when we came off it as there would have been if I had driven forward onto it. Hence one ramp forgotten and not missed until 400 miles later.
If you happen to have been to the site at Moulin de Avergne at Pons and found a ramp, please accept it with my compliments !