Maybe, but I still think if you did it that way it would be a waste of money... not a waste of money in that I3G isn't working, but a waste of money because you shouldn't NEED to take any supplement when you do your weekend re-feed. On the AD, as you well know, your body should be depleted enough to where you only need to let the food/carbs do the work.
Also, I would venture to say I3G would work a lot better with cleaner carbs. Do you use all clean carbs in your re-feed?... I bet there's some cheat stuff sprinkled in there. You would have much better results if you just bit the bullet, spend the money, and take I3G everyday with clean carbs. It's only 12 weeks, man. That much time off AD won't kill ya and will be a nice change of pace.