I'm just gettting start FL-III also (2nd week). To answer the original question, you won't really have time to change the weights in the middle of a giant set - the idea is to move quickly from one exercise to the next. Although "quick" is not exactly how I would describe those last couple of sets....
George - I just looked over your training log - nice job. I would like to know how effective this was for you, in terms of fat loss (we're similar age and starting BMI).