It is hard to say because CD doesn't really allow for a carb meal on 810 -- you would have to go up the plans for that (1000 cals plus), but generally, when you start the Atkins diet you are on 20g of carbs daily to get into ketosis, and as you correctly point out some of the bars contain more than 20g of carbs.
You may find you can still have a good weekly weight loss with the odd small serving of carbs but don't skimp on your CD packs to fit it in -- or you will be in trouble as you will not be getting all the nutrients you need!
As a general rule, you should never eat more than 20g of carbs in one sitting to stay in ketosis, and check an hour after to see if you have been knocked out of ketosis.
hope this helps