Thanks for your help.
I trashed the preference file, but this didn't solve the problem. I know the preference file is being saved correctly because when opened with a text editor I can see the save path in plain text, which is different than the default. Unfortunately, the reset of the file is not plain text, so I cannot change compression settings that way.
It's pretty clear to me that the software is bugged. In fact, I noticed that when the Tivo file is automatically compressed, a 3rd resolution is used, which is smaller than 640x480 and not the 1280x720 resolution I desire.
I've given up on the software and trying iTIVO as a substitute.