2014 - 2017 Tundra Sonar Sensor False Detection

Have periodically had false alarms from the front right sonar parking sensor. I have always just wiped it off and the alarm stopped. It has become more frequent and now I see a TSB addressing the issue (T-SB-0277-17). My 2017 Tundra is within the VIN range called out in the TSB. I have not asked the dealer yet if they will charge me for this as my Tundra is out from under warranty (44,000 miles) but intend to do so. I have the procedure to install the silicone spacer spec'd in the TSB to electrically isolate the sensor from the metal front bumper and it looks straight forward. The back bumper on my limited is composite so I don't think I need to do anything there. I was surprised that I was quoted $27 each for the silicone washers from my dealer (I think they are eaches and not a set of two?). I thought they would be a couple of bucks each. McGeorge Toyota has them on-line for $13 each so that dulls the pain a little. Has anyone had this done? Did it fix the issue? Do I need to replace the retainer clips per the procedure?