Syn help please - Cheese Sauce

I'm doing a roast dinner for 4 later and others have asked if I will make a cauliflower cheese so my question is:

I have the Asda basic cheese sauce mix in my cupboard, SW site tells me its 10 syns on all plans, if I was to have some how many syns would it be for me???

I would make that 2 1/2 sins.

Did the same with colemans beef casserole mix yesterday. worked out 2 sins per portion.