I have found additional information to support my counting only 1/2 the carbs from sugar alcohols.
In August, 2005, Dr. Eades (co-author of Protein Power) posted a blog entry regarding sugar alcohols (http://www.proteinpower.com/drmd/archives/2005/08/Sugar_Alcoholic.html). In the blog entry, she stated:
"Our sort of ballpark standard means of calculating their effective contribution to a low carb diet, crude at best, is to count as usable about one-third to one-half of the sugar alcohol grams in a recipe or food. For instance, say the nutritional label of a protein bar proclaims 20 total grams of carbohydrate, 5 of which are fiber, 3 of which are starch and 12 of which are sugar alcohols. The label will likely state--usually in a big red or yellow starburst--contains only 3 grams net carb! Really? Depending on which sugar alcohol(s) contributed those 12 grams, some portion of them will be absorbed to contribute calories at the very least and raise blood sugar in sensitive individuals at the very worst. And, of course, what's not absorbed contributes to the gastrointestinal symptoms that occur with some of them. It would be more correct (not to mention more prudent for people struggling to lose weight and for the diabetic population) to count at least 4 and possibly 6 of those sugar alcohol grams as having an effect, for a total of 7 or 9 net grams. Just doing that little bit of math may help keep your weight loss going or your blood sugar in better control. "