I wrote the plugin following UPS’ documentation. Your case is unique, as you don’t want DC to be available in the scenario discussed. To do that, you’ll need to override the XML response returned by UPS. I added the filter a couple of releases back to handle precisely these kinds of cases. In order for me to add something that would work for everyone, I’d have to mess with adding admin options, making sure I don’t get any regressions and so on.
Using the filter can be done by any WordPress developer, and without modifying my plugin’s files (which would mean you’d be stuck on the current version, as updating would make your custom changes go away).
As for receiving compensation, I’ve spent much more time discussing the issue with you than I would spend actually writing the code. I give free support, yes, but code customization is not free.