Sugar free syrups - are they carb free?

According to one of the suppliers:

Monin O'free Sugar-Free, Calorie-Free Syrups, 1 litre bottle (large). Sweetened with Splenda and Erythritol natural sweeteners. Fat free. Low carb (total 4g carbohydates per 30ml serving).

Nutrition information based on 30ml servings, 33 servings per bottle: Calories zero, Fat zero, Sodium zero, Carbohydates 4g of which sugars zero, Protein zero.
no idea how it can have no calories but 4g of carbohydrate .

Yes that is odd isnt it phoenix? I would imagine it is just the Splenda

Which begs the question why not just use Splenda? I'm sure it would be cheaper...

Splenda doesn't taste of Hazlenut, or Vanilla , or caramel. Personally I find they are sickly sweet so I just ask for 1/2 a 'shot' in my coffee

yeah i was a bit confused over this one - I ordered Sweetbird Hazelnut sugar free syrup and it says on the nut info that there is 0g sugar in it... funny tho cos it has a worse impact on my BM's than when I have one from the Coffee Shop?! Is there anyway of accurately testing the syrups?!