Just wondering if its ok to have atkins advantage bars once and awhile when on OWL?

Don't know. I just stay away from them altogether. I'm afraid they will cause my cravings to reappear.

I think the answer depends on how the bars act on your body. For me, I can eat 1 to 2 a day and still lose 1-2lbs a week.
For me its a breakfast relief, since I am allergic to eggs and cheese.

I wanted these bars too... but they were causing me to stall. Apparently they do that for a large number of LCers. Use with care....

I've used them from Induction on without problems. However, some people are sensitive to the sugar alcohols they contain & are even stalled by them. So try them & see how they effect you. It's yet another one of those YMMV, your mileage may vary, situations. You need not avoid them altogether out of fear, just monitor how they affect your progress. Don't eat more than 1 or 2(max) a day. I personally like the chocolate peanut butter best. Good luck.
God Bless,
Amy-Lynne