Dr B notes that from experience these measurements of food act similar in carbs. (ie: 2 c salad=1 c cooked veggie=1/2 c mashed veggie) His point is that foods, when digested can have similar effect on BS even tho' amounts are varying. It has to do with how easliy foods are broken down by the body, cooked easier than raw, mashed easier than chunks, etc. The point behind the salad thing I think is what he calls the "chinese food effect", even tho' salad may be lower in carb, over filling stomach will slow down digestion and have adverse effect on BS.
You should test, test, test after eating and introducing different foods and amounts to find what works for you.
Good luck with your journey...