If and only if you can get the exact same deal. It is not just a matter of wording. There is a world of difference.
Granted Costco does things their own way sometimes, but I have to respectfully disagree. After working more than 30 years in the retail business for a few different places a merchandise exchange is exactly what I said, a return and a new sale, just in the same transaction (or at the same time). All the places I’ve ever worked ALWAYS gave the customer the benefit of whatever price was better; the price at the time of original purchase, or the price at the time of ‘return’ even if it meant giving the customer money back to boot.
To do any differently or take advantage of some ‘coupon or limited time offer’ loop-hole would not only p!ss off an already upset customer, but likely alienate them (and anybody they might influence) for life. Not good business practice!
If you re-read my post, I suggested taking another unit with him ( if available) to the CS desk and explaining that he wanted another one at the same price as he bought it for a few days earlier. This is not an un-reasonable request, nor would I see it that way if I were behind the counter.
But like I first said, Costco makes their own rules sometimes, so never assume that standard business practices always apply. You should always as a customer, ask & verify what you want prior to committing to a transaction. That’s just common sense.