No, the difference is larger.
The 825GB of the PS5 are "marketing" GB, which translates to 768 "real" GB.
The TerraByte are 1024 "real" GB, so the difference are 256 "real" GB between both
"real": 1KByte = 1024 Bytes
"marketing": 1KByte = 1000 Bytes. Marketing loves to use it for advertising the size of Harddiscs because it sounds more impressive. Some apps use it to make it easier for the users who do not know about the 1024 thing
The usage of the "marketing" GB was confirmed by Mark cerny around the time of his march talk, when he said something like that 825GB is the logical size because they are using 12 channels and 12 chips, and 12x64 = 825.