Syns - a little clarification please

On the advice of other members I have picked up 3 tins of Asda's chickpea dahl for lunches at work (as I can get rice from the canteen) and whilst there got the vegetable balti too. I checked sysn when I got home to find, yes the dahl is indeed syn free but the balti is 9 syns for the tin.
Why? It is less cals etc??? Am so confused, and now have 2 tins of veg balti I won't eat, lol

I suspect that if you look at the ingredients there will be a reason - maybe oil?

Thanks Circes, as usual a mine of info. It would figure that something so nice would be high, lol. Mind you, I'm loving the chickpea dahl which is cheaper anyway.