Hmmm...as someone already suggested earlier, maybe it was the black paint. I had been using #20 for over a year, and recently went with
AIO/SG because I found the #20 durability to be not great for a car parked outside. Last year, my car was in the garage at nights, but now my wife parks in the garage.
I have found the #20 to be mostly gone after 6 - 8 weeks when parked outside, and now that I am using AIO/SG, I have found the
Klasse to last 3 months or so. The #20 was easier to use for sure, and beaded like mad, but it wasn't up to being outside in a rainy climate all winter.