Network and Local Configurations

We are going through a large PC refresh and a significant number of our new machines will be laptops. We are trying to work how to have the configuration (cfg) available to the laptop machines when offline. We have set up a sync from the network to the local machine for the cfg. and I have edited the ConfigurationSetup.cfg as follows;

[General]
_PDT_nDrv = M:/
_PDT_lDrv = C:/
_PDT_locCFG = PennDOT_CE_Configuration/

%if exists ($(_PDT_nDrv)$(_PDT_locCFG)*.cfg)
   _PDT_Drv = $(_PDT_nDrv)
%else
   %if exists ($(_PDT_lDrv)$(_PDT_locCFG)*.cfg)
      _PDT_Drv = $(_PDT_lDrv)
   %else
      error Exiting, No network or local Configuration found
   %endif
%endif

_USTN_CUSTOM_CONFIGURATION = $(_PDT_Drv)$(_PDT_locCFG)

[SetConfiguration]
%if !defined (_USTN_USER_CONFIGURATION)
%if defined (_USTN_CUSTOM_CONFIGURATION) && ($(_USTN_CUSTOM_CONFIGURATION) != "") && exists ($(_USTN_CUSTOM_CONFIGURATION))
_USTN_CONFIGURATION = M:/PennDOT_CE_Configuration/
%endif
%endif

Unfortunately line 21 doesn't seem to like being redefined to a new value.

Here is my debug for this section, note line 9 and 10;

    Processing macro file [C:\ProgramData\Bentley\MicroStation CONNECT Edition\Configuration\ConfigurationSetup.cfg]
      (System): _PDT_nDrv=M:\ [M:\]
      (System): _PDT_lDrv=C:\ [C:\]
      (System): _PDT_locCFG=PennDOT_CE_Configuration\ [PennDOT_CE_Configuration\]
      Starting skip to endif, [C:\ProgramData\Bentley\MicroStation CONNECT Edition\Configuration\ConfigurationSetup.cfg], line 27, depth = 0.
      (System): _PDT_Drv=$(_PDT_lDrv) [C:\]
      Starting skip to endif, [C:\ProgramData\Bentley\MicroStation CONNECT Edition\Configuration\ConfigurationSetup.cfg], line 32, depth = 0.
      endif, [C:\ProgramData\Bentley\MicroStation CONNECT Edition\Configuration\ConfigurationSetup.cfg], line 34, depth = 0.
      (System): _USTN_CUSTOM_CONFIGURATION=$(_PDT_Drv)$(_PDT_locCFG) [C:\PennDOT_CE_Configuration\]
      (System): _USTN_CONFIGURATION=M:\PennDOT_CE_Configuration\ [M:\PennDOT_CE_Configuration\]
    End of macro file [C:\ProgramData\Bentley\MicroStation CONNECT Edition\Configuration\ConfigurationSetup.cfg]

I have also tried to defining line 21 to use a variable and not be hard coded but that doesn't seem to work.

_USTN_CONFIGURATION = $(_USTN_CUSTOM_CONFIGURATION)

Any help on how others would be handling configurations for laptops would be helpful. I would prefer to not use different icons for Network and Local configurations.