2012 Prius SofTex Heated Seat Discomfort

My 2012 Prius is not the first vehicle I have with heated seats. I have a 2005 Honda Odyssey that, other than turning them on, I would not know had heated seats. That sounds like a strange thing to say but...

My Prius driver seat has a noticable bump in the rear seat bottom. That bump is some part of the heated seats. I have a tailbone. My tailbone would love a nice soft seat or nothing at all but that disc shaped crap is there to push on my tailbone so after driving for more than 3 hours, I have a good amount of pain for the rest of the drive and for a while when I get out. It goes away, but I have recently had some 10 hour drives.

My solution was to pickup a "Tush Guard" seat cushion from Amazon. It solves the problem at the expense of a thick cushion on my seat that pushes me higher and kind of messes with the position of the lumbar support.

Does anyone have a suggestion or has anyone ever dealt with this problem and found a reasonable solution. I have to believe that this car must have either a heated seat mechanism that has moved, or cushions that have compressed SIGNFICANTLY. What puzzles me is why toyota would put anything other than a pad under your rear end. The placement of the disk thing is so absurd that I am thinking things have moved.

The wife says that the passenger heated seat is not uncomfortable... I haven't sat in that seat for hours and may never wind up in that position.