The last CPU I had on UA was in my last days of Platinum in January 2015 on CLE-IAH-SJC, both legs. The closest since then might have been #14 on the CPU list.
I got a CPU on AA going DFW-RAP in September, and that's with Air Berlin Gold, (~AA Platinum ~UA Gold). I had 50+% CPU's on CO with CO Silver in 2009-2010...