Visual Studio Installer TARGETDIR location

I'm using a visual studio installer project to install my addin.  I've done this on a 32Bit version of SWX a few years back and I used as Custom Action to run a .bat file from a command window.  The custom action ran cmd.exe with an argument of /c "[TARGETDIR]\Register.bat" which worked fine.  However now with 64bit SWX 2017 it appears that the installation folder is C:\Program Files (x86)\... but I believe the TARGETDIR parameter is pointing to C: \Program Files and therefore my install fails on the commit step to run the custom action.  I have the project being compile for Any CPU.  I've tried messing around with setting it to x64 but I get compile errors with that setting.  Anyone have the magic incantation to make this work or a different way to register the add-in during install that would work better?

SolidworksApi macros