My 2004 model has 9 settings on the front, so at some point they must have changed shocks and not the manual.
There is only one shock listed for the GS, but the GSA has a different one
Sorry, I was wrong (or unspecific) again...
Mine is an 06 USA model non ADV and only has the five positions on the front...
...not at all surprised that they changed the shock and didn't change the manual, but I should have looked at some earlier bikes before posting.
When riding on the road, I have never bothered changing Telelever preload on any of my bikes going from light load to heavy load (or even two up on those odd occasions when my wife would rather drink than ride) but I do take the minimal trouble to crank the rear pre-load up when heavily loaded or carrying the wife.
I suppose I could be incrementally adjusting the front constantly for the absolute ultimate best adjustment, but frankly, I couldn't be bothered...
...and since I seem to have done OK all those years where I didn't have any front end spring adjustment at all, even my obsessive compulsive nature is not overcome by my intertia.
The rear shock, on the other hand, is worth adjusting when changing load by a fair bit, if only to keep the headlight beam aimed correctly.
When you are two up and the headlight no longer aims low enough, you can EASILY adjust the beam with the little cam-over flip lever that provides a gross adjustment for the light. I usually forget it's there, but it is much easier than turning the nylon hex-knob that sets headlight angle.