Inadvertantly discovered that if I run Analyze in CCleaner v5.04.5151 then close the program and run it again it gives a different number for amount to be cleaned.
The first time I ran it it gave 33.7 MB, the second time 167 MB, the third time 33.7 MB, and every time thereafter.
I would simply dismiss this as a glitch of some kind except that 167 MB is more in line with what I'd expected.