Let' put a finer point on it. It doesn't work very well, "for the cost" or otherwise.
Why not see if the owner wouldn't consider a Toto Entrada, which can be had at a professional price for less than $200.
In fact, although I would never recommend something like a Glacier Bay, the fact is that its most recent crappy foreign-made toilet has a 3" flush valve and actually flushes pretty well and doesn't look bad. (A friend's contractor put two in her bar, and after six months they haven't broken and don't clog often. Admittedly, my low expectations probably helped drive my surprise, but a "not terrible" rating by me is a step up with what you're going to find with that Alto or that Maxwell.)
Also, given that they are putting in antiquated round-bowl toilets (rather than elongated) to save money, the round Glacier Bay is right in the same ballpark, if not cheaper. But the Entrada would be absolutely stellar as compared to any of these.