Yogurt is tricky.

Active cultures often consume a great deal of the carbohydrates, reducing the overall carb count.

If I recall correctly, these say they have 80 calories -- 15g of carb, 5g of protein.

Splenda is non-nutritive and thus NEVER appears in carb counts.
You can't say thusly that it has "15g of carbs, but it's all splenda."

The carbohydrates are from the fruit in the smoothie and from the lactose in the milk that they use.

My wife has had them a few times, and since it's hard to say exactly how much to count them as, we've assumed 5.

Note, we've both been somewhat stalled lately, so if you're going to try them, best keep them as an infrequent treat.