Well, there are different kinds of deductible carbs, and it's a YMMV issue (Your Mileage May Vary.)

Fiber, being indigestible, doesn't impact your blood sugar and in fact slows up carbs moving into your bloodstream. I easily deduct those, as do most people.

Sugar alcohols, (the malitol, etc, usually end in "ol") are a form of artificial sweetener and have varying degrees of impact. For malitol, I've seen the figure of 50% tossed around. Diabetics and those with access to a blood glucose meter can tell for certain, and of course, should. Since I don't have one, I just go by my feeling of hunger afterwards. Atkins bars are satisfying for a few hours, so I feel I get along with them. Other brands of bars make my body act as though I'd just scarfed down a couple of twinkies instead, and make me ravenous afterward. Those I avoid, and I would count the gross carbs

Other artificial sweeteners are likewise YMMV. I've seen diabetics post that malitol makes them spike, but Splenda has no effect, so they would feel better eating something sweetened with Splenda. These would be deductible carbs for them.

The way the labeling law was written, pre-Atkins boom, anything that isn't fat or protein gets lumped in with the carbs. That's why dissecting a label can be tricky.

One firm opinion often expressed on these boards is that too heavy a reliance on "frankenfoods" will not get the results most people want.

But the occasional low carb ice cream bar was never a problem for me, and they are usually sweetened with Splenda, which most people don't report a problem over. I would go with the net carb, myself, unless you find yourself stalled and want to drop those temporarily to see if that is the cause of the problem.

My biggest guideline, now that I'm maintaining and experimenting, is how my body reacts to the new food. I've been indulging in occasional wraps that aren't Atkins, but they are stuffed full of high fat & protein fillings and I'm getting along okay. But I picked up some low carb bagels last week that made me feel like I was starving two hours after. For some reason these were messing with my blood sugar, and I have to stay away from them.