Our friends at AboutWeb, who host our local LiveCycle user's group, helped me figure this out; however, I think Adobe has some usability issues with this feature. It has to do with the Automatic vs. Custom options on the Tab Order tab. If I select Automatic, dynamically added table rows are correctly inserted into the tab sequence. If I select Custom, dynamically added table rows are appended to the bottom of the tab sequence. The problem was, even if I just display the Tab Order tab, the Custom option is automatically selected. Something I completely missed. Hopefully this post might help anyone having the same troubles I did.