How much liquid do you typically lose in the primary?

So I just bottled my barleywine. It's been in the primary for just over a month, and it has CRAZY yeast activity the first week. That said, there wasn't too much blowoff (maybe 1/4 gallon MAX). 6 gallons went into the fermenter easy, and when I bottled today, I siphoned 5 gallons of beer off the yeast cake.
So... is it typical to lose 10%+ of the liquid in a batch due to the yeast cake liquid? When I make 5.5 gallons of whatever, I invariably end up bottling 4.5 gallons. Sealed fermenters... so I dunno where it's all going.

it is not too uncommon to have to leave behind 1/2 a gallon in the fermenter.

Most recipes call for 5.5 gallons to account for that.

I usually brew 5.75 gal post-boil, and I end up with about 5 at kegging.

I lose 0.5 gallons to whirlpooling & the resulting trub after boiling, and around 0.25 gallons in the primary.

Alright, I just wanted to make sure this seems to be typical. I usually shoot for 5.5 gallons, but sometimes my extended 'almost boil' (stovetop ) results in less than 5 into the primary.

When I brew 10 gallons I always try to put close to 11 into the fermenter. I usually end up perfect when filling two 5 gallon cornys at time of kegging. On a rare occasion I will have a little extra in which I bottle a beer or two to savor after I kick the kegs.

6 will get me 5 into the keg after primary secondary fermenters so my batch size is 6 gal

I only brew 3 gallons so adjust accordingly, but I start with 3.75 gallons, boil off to 3.25, get 3 into the primary and 2.5-2.75 into seconday/bottling.