If a color theme is embedded in a MS template, is there a purpose for a .XML color theme file?

I created two MS color themes for a client, gave them the XML files, and instructed them on the correct filepath to install them locally.

Later, we were asked to build templates (DOTX, XLTX, POTX) with the color themes embedded. Again, we sent them the templates, and instructed them the correct filepath so that the templates would show up in New from Template / My Templates.

Now the client is questioning WHY the XML was necessary, why I advised it, etc.  I wasn't able to answer satisfactorily.

Can you shed some light for me?

Disclosures: 1) I'm a freelance designer, not a programmer. 2) The client hired a design firm that brought me on to work on the MS end—so I'm one step removed from the client relationship. 3) I use MS Office cloud on Mac, while the client is on MS Office 2010, on PC, running an older Windows OS (not sure which). And 4) part of the client's objection/dismay is that hundreds of people cross-enterprise need the templates and/or XMLs; my suggestions/questions to ask their IT dept deploy them have gone unaddressed, no idea why (see #2).

Thanks very much—

ed hart
grafhartwerx design & production
grafhartwerx.com