The reference horizontal in those photos is actually a 6' level, as I was verifying the floor & lift are both level. The lift arms deflect downward on both sides, but most of the deflection seems to be due to the overall platform weldment (two main channels joined by cross members) flexing...
Have you looked at how much the load arms and platform channels are deflected when under load? I just got a new SL-6600 and am a little concerned about this. Lifting a 4500-lb Honda Pilot, the load arms deflect downward an inch or so, and the platform channels tend to twist or deflect so the...