Yeah, I tried that already, so all of this testing has been with the soft check feature on, and still the override doesn’t work on the modified URL.
If there’s nothing else I can try, I think I may have to accept that I can’t modify the default search results page URL and still have Ajax Search Pro work correctly.
If I have to choose between modifying the URL and using Ajax Search Pro, then I choose Ajax Search Pro, but if you do find a solution at any point, I’d love to know about it.