I'm sure you've seen other discussions surrounding the idea of 'shoring up' any slide rooms while parked, but the idea of actually trying to change the level of the slide is a different story, as that would entail more of a 'jacking up' of the slide, possibly creating a situation where the pressure would damage the slide mechanism.
While it's possible that the slide is working fine, it sounds like it may need some adjustment so that the 'drop' is not so severe, or at all.
It seems as most slides have some sort of 'tilt' or unlevel movement while retracting and extracting, like on ours, though we don't notice any major unlevel'ness' when the slide action is complete, or even when it's not fully extracted - but we also have the electric slide rail system, and not a hydraulic one.
'14 Palazzo 33.3 bunkhouse 34' diesel
KingTailgater2 Dish HD, 100w/5a SOLAR, BlueOx
100,000+mi since '14 - US, Alaska, Canada - Hiawassee, GA! (also, '14 Gulfstream Amerilite and '07 ForestRiver Rockwood) : )