It may not be 100% correction in a case like this, but if it gets you 80% there, then that may be the best I can do for now.
80% may be a little over-optimistic. 50% would be reason to celebrate. Please take some measurements before and after. Without objective measurement, it comes down to "yeh, that sounds better, I think".
(Sorry, Danny, I know "objective measurement" sounds a little like science, but if you're ever going to convince the propellerheads to share your belief in this product, eventually you're gonna have to back it up with numbers.)
A waterfall plot will reveal not only what ARC is doing for you but also what it's not (and can't). Frequency response is not static; it changes over time. That's what a waterfall plot shows you: frequency response over time. You'll find that some frequencies ring out much longer than others (the result of constructive interference caused by room resonances). ARC can't help you with that other than to turn down the volume of the worst offenders. Only absorption can help with that.
I am not trying to dissuade you, Mike. Given your circumstance - not being able to install acoustical treatments - I would have no reservations about using ARC myself.