So unfortunately I had to buy a full new set of tires. The Minneapolis service center prediction was wrong. I am now at 26,000 miles and decided to replace all four. Two of the tires may have lasted a little bit longer but did not seem worth the trouble to deal with the issue again in a couple of months.
With the original equipment Continental tires, they lasted 20K miles on the front and 6K on the back. The pair of Michelin tires I purchased this year lasted 7.5K on the back and 6K on the front. I may have been able to get a little more mileage out of the Michelins. I decided to purchase the Continentals as they appear to have slightly better longevity but I really am just guessing. The Denver service center implied that the low wear was due to the usage of the low suspension setting. I am not going to use this setting unless I need extended range.
Another fact that I found surprising is how much my car was out of alignment again. If you look at the detailed report below, the tires are out of alignment particularly with the rear toe. The shop owner indicated that some of the bolts were not particularly tight. The overall alignment numbers are actually worse than the earlier problem I reported. The local garage suggested that I stop by again in 1,000 miles to see how my alignment is holding up.