When using a variable (instead of a numerical value) for a parameter in VSS, the units are specified in base (SI) units instead of following the user-specified project units.
Go to Options > Project Options from the main menu.
Under the Schematics/Diagrams tab note that by default the Unit Normalization option for System Diagrams is checked.
This default setting retains the behavior from previous versions where base (SI) units are used for all variables and not the user-specified units in the project.
Thus any existing VSS projects from previous versions will still calculate the same results in version 11.
However, if desired, this behavior can be changed to use the user-specified units by unchecking the button for System diagram dependent parameters use base units.
One may also choose to make this behavior permanent for all future sessions.
Go to Options > Environment Options (see figure below) and make the desired changes under the Schematics/Diagrams tab.