Rear Suspension problems of the 2007 Honda Pilot

I bought a 2007 Honda Pilot ex-l 2wd. I am disabled, so I require a hitch, electric chair lift to carry my electric wheelchair. I previously had a 2003 Toyota highlander 2wd, 4 cyl, with the exact same configuration. Since I have adapted my 2007 Honda Pilot with the equipment, I have found this vehicle is not capable of carrying the tongue weight load of about 350 lbs, which Honda published is adequate (I. E. Honda states a 2wd Pilot is capable of towing 3,500 lbs and a 4wd is capable of towing 4,500 lbs, which equates to an allowable tongue weight of 10% of towing weight which is 350 lbs for the 2wd and 450 lbs for the 4wd). I have spoken with the chief mechanic at hollywood Honda; the hitch experts; professionals at my wheelchair/lift facility and everyone agreew the 2007 Honda Pilot can not carry the tongue weight of 350 lbs in a safe and effective manner. The vehicle starts to lower the back end and the front end starts to lift upwards as the weight of the wheelchair on the lift starts to ascend. When the back end of the Honda Pilot has "bottomed out", then the wheelchair and lift start to ascend. When the wheelchair and lift ascend to its proper height as designed by the lift manufacturer, the lift and wheelchair are in a very vulnerable position which is not high enough to keep the lift from bottoming out and the entire wheelchair and lift from "bouncing" in manner which is uncontrollable, whcih gives the sensation of being out of control. Meanwhile, the front end of the Honda Pilot has escalated about 6 - 8 inches above its normal level plain. If Honda has conducted its evaluations in a satisfactory and safe manner as they publish a 2wd Honda Pilot can tow 3,500 lbs and a 4wd Honda Pilot can tow 4,500 lbs, then why can't the Honda Pilot effectively maintain the normal tongue weight of 10% of the towing weight which they stipulate? if you can assist me in making some determination pertaining to this issue, I will be gratefully appreciative.