Binoculars
My suggestion would be the same as my response to the original post, 'If it aint broke, don't fix it'
To my mind that extends to carrying out unnecessary tests on your 'perfect working order' PC, and then starting to question the results. You know your PC is fine, I know its fine, who cares if Windows defrag isn't wonderful?
You can fdisk, do installs, defrags, etc. You know when something is wrong, you don't need these things. Clearly you're right, Pitstop is wrong; never use it again until something happens to give you reason to suspect the PC is playing up.
Testing for testings sake, and you end up sleeping on the Embankment...
bug