Woolies are you breaking the consumer protection act?

Woolies why is it that whenever I buy your cream cheese tubs the quantity is always less that the stated amount? And yes even though it always seems to be, only say about 4%, 10g less than the amount stated on the container, 240g instead of 250g that is not the point. In baking the exact amount is necessary. I can only assume the same is applicable for your other cheese tubs. As far as I am aware the contents, legally have to be at least the advertised amount.