Incorrect size after cleaning up a filerepo folder

Hello !

Got an issue with my laptop over here. It's an Asus ROG...and no, i seriously doubt that asus forums would help me, been there in the past.
It came with a 120 GB NVME SSD alongside a 1TB HDD.
As time passed, space kept clogging up on C from .NET, Visual Studio, SQL Server and the usual apps ( i keep NO games on C: and all of the programming apps and technologies aforementioned require me using the C: drive), so...
tonight i decided i need some space
I was at 20+ GB free...
Then i noticed in

C:\Windows\System32\DriverStore\FileRepository

i had quite some space (close to 26 GB) used with nv*.inf* folders (basically full drivers from previous nvidia installs)
Since a clean install on nvidia drivers didn't actually clean those 26 GB, i turned to trusty PowerShell and a bit later i shrinked it down to less than 3 GB total ( just moved old version drivers folders to the 1TB drive).

Now i'm left dumbstruck as the total FREE space, expected to be around 45 GB...is actually a bit under 27 GB.
Can someone explain this ?
I sure can't. Or is it in windows world that basic math doesn't work ?
I did check after i moved them the folder's size.
The 1 TB drive does infact show it's "gained" those 20+ GB..but C: sure as .... didn't lose 20.

TL;DR version:
Start with 120 GB SSD with over 20 GB free (23 iirc).
Move over 22 GB from C:\Windows\System32\DriverStore\FileRepository to the 1 TB drive (old nvidia installers drivers folders)
Expect 40-45 GB free, notice infact it's close to 27 GB free only.
Help ?

P.S. : It's my 1st post in these forums, hope i didn't break anything.