Yep. I sure don't recall ever downloading ASIO4ALL on that pc, and the only options in Sonar were WDM and MME, so I didn't realize ASIO4ALL was installed. I guess adjusting the latency outside of Sonar, in the M-Audio control, triggered a setting inside Sonar. After that, Sonar's driver list included ASIO for the first time.
I saw a YouTube vid where something similar happened to the instructor when he selected ASIO - Sonar defaulted to ASIO4ALL even though ASIO was checked. There was also a vid stating WDM was the Sonar recommended default, and the X1 Power book says either WDM and ASIO are acceptable...but, until you guys asked about ASIO with the Fast Track Pro I didn't know it was an issue.
I certainly know more about audio drivers and Sonar than I did before. So again, thanks.