The network drive generated with the PC client shows the same drive information as the local storage, because the local storage is the limit for how much data a user can have on his device.

In this (the below image) the user can only make ~210 GB of data available offline by using offline sync, but the User can still have access to a much larger file structure on the server and access all this data by double-clicking the files.

This indicator can't be changed since the user can have access to multiple companies with the same client and therefore it would not give an accurate image of the space available.