The loss of the rounding-up to 500 miles, together with a ridiculous price differential and the fact that the last flight home looks oversold (.bomb won't let me select seats and shows every seat in Y occupied), did the trick. MDW-CMH-MDW on WN, even with Business Select (fully refundable, A-segment), is $300 less, so I did it, holding my nose.

I'm not sure what this means for UAs economic model, but I have 1P in the bag for next year, and probably won't get close to 1K (though if I do, a Dec. MR will make up what I'm losing from this trip).

The actual RT miles plus 1P bonus weren't worth aggravating my clients with the higher fare (or me swallowing the difference)...and yes, if I were rounding up to 500 miles, I might have stuck with UA -- stupid Pavlovian response to UA marketing on my part, but them's the facts!