The Extra Easy cookbook incorporates the superfree in the recipes, and don't mention you have to have an additional 1/3!
When I rejoined SW in May last year the 1/3 was more of a recommendation than a rule. I love my veg, so for me the 1/3 is normally pretty easy anyway but I don't have it with every meal. Sometimes I have more than the 1/3, and sometimes none at all!
I think SW have made the 1/3 ruling to discourage people to fill up on carbs.