I never question SW and what is/isn't free - I just eat the food they allow and watch the weight come off!!
Batchelors Savoury rice is equally as high in cals but also free!
I think the theory is that you can only eat so much of it, you wouldn't eat, for example, 3 packets.... and also you are restricting other foods such as A/B choices and the treats.
Don't worry about calories, it's not how SW works!