I have a Verbatim 25GB 6x blu-ray disc. Before I burned anything to the disc Windows 10 said total size 22.5GB. Now after I burned 20.4GB onto the disc, Windows 10 now says total size 22.3GB.
Does this sound "normal"? First time burning a blu-ray disc successfully, always burned with CDs and DVDs and never noticed this before. Never had this happen to a CD, DVD or DVD+R DL.