These applications use one file format, so there's never two versions of the same file. Newer versions of the Mac OS even include common PC fonts, e.g., Arial and Times New Roman. Even Microsoft touts the cross platform capability of its Office suite. Application licenses can be used for either PCs or Macs. There are no additional costs.
Licenses allow use of one application on one computer, regardless of platform.
Future IMS access from personal computers will no doubt use Internet protocols for browsing, finding or submitting information. Both PCs and Macs use Internet protocols. Technical support systems within the agency are cross platform and available to staff from all divisions and departments. Some schools have standardized on a particular computing platform, while many others are cross platform. It might be more efficient to train a small number of tech support staff on the Mac OS rather than many staff members on Windows.