Dynamically change "Load Headers" on modAction?

Here’s the situation:

I have a custom manager page for which I have an action and a menu item. A user can click the menu item and see a report generated within the MODx manager.

I’m wondering if I can use that same controller to also fire off an XLS download... it’s the same query, but the output would instead use its own headers.

So my question is "Do I need to create a new action with the "Load Headers" left unchecked?" Or can I turn that off on the fly so my download occurs correctly?

Or conversely, can I leave "Load Headers" unchecked, then manually load MODx’s headers when needed? I would omit loading MODx headers when I needed to trigger a download.

Does that sense? Or is there a better way to go about this?