Huge disk space difference between OmniDiskSweeper and System Information views

Dear community,

From System Info perspective, there are 170 GO used spaced (with 1

20GO used by "other users")

See below :

This is confirmed by TimeMachine backup size evaluation

See below :

Whereas when I do run OmniDiskSweeper (as root), it shows only 55GO used disk space => 110 GO différence !

And 110 is closed to the 122 of "Others Users"

User is "only" 22GO

It does not seem to come from TimeMachine.

Any ideas ?

Thanks in advance