Often the system administrators are not happy with having a part (Modeling) of the installation in c:\program files and the other part (Drafting) in c:\program files (x68) on 64 bit Windows 7 systems.
If you change the path during the installation process to c:\program files it is silently changed to c:\program files (x86). This is done by the installation program to obey to a a kind of Windows 7 "style guide" that likes 32 bit programs to be in c:\program files (x86).
If it is necessary to follow this style guide the administrators will understand this, but silently changing the location is a no go. At least a message box should appear.