So if I did an Ab exercise instead of the stationary bike as a HIIT routine, I would get spot reduction? It seems doing something like that would hose the rest of your workout. I definitely agree with using the stationary bike for HIIT.
No. As the study proclaims, the fat goes through lipolysis, freeing up the fat cells. If done right before a workout geared towards fat burning, i.e. a circuit based workout like the one I have provided, or HIIT, it has the potential to burn more fat from the "worked" area. A quick twisting crunch tabata(4 minutes) before said stationary bike HIIT and workout shouldn't hurt your lifting that much, especially with this rep range. Concentrate on the eccentric(lowering) phase of each movement and you'll do fine.