I've tried the UHMV slick tape mod, I've polished the pellet feed ramp with 0000 steel wool, and I still have problems with the pellets not sliding/dropping down to the auger chute. The grill is level checked with a bubble level.
I've read several posts on several groups about placing some type of vibrator on the pellet hopper to shake the pellets down to the auger chute.
I ordered a small concrete vibrator from Amazon and it came in a couple of days ago. My plan is to mount it as close to the auger chute as I can, run an intermittent timer connected to the vibrator, and not have to worry about checking on the pellets every hour or so on long cooks. I tested it out just by holding the device tight to the outside wall of the hopper and it worked as I hoped, and am sure it will work better when permanently mounted.
See Video Here