LOL!!!
that's why I make 12gal batches - I realistically get 11-11.5 or so in the conical, and then don't mind dumping a half gallon or so. gotta let it really compact, in my experience - takes several hours - and I admit, I never get it all, but its highly reduced.
I did a visual comparison once of jars of yeast saved from APA and IPA batches - the APA I'd dumped the CB and then reused the slurry on the IPA - I'd forgotten to dump on that one. The saved yeast slurry did *look* more pure on the APA but of course there are many variables at play, but it was enough for me to say, yeah, it does some benefit.