don't think about the calories. you could eat 10,000calories a day and stay in ketosis. it's carbs you need to limit. lots and lots of people on CD have a bar every day after week 2, and remain firmly in ketosis. the chewy ones do have more carbs than the other products, which is one reason why you can only have one bar a day, but the total carbs will still be low enough for the overwhelming majority of people to stay in keto - otherwise CWP wouldn't sell them!
the thing with ketosis is it's harder to get into than to stay in - which is why you have to be more careful in the first two weeks.
there's about 25cals extra in a bar, btw. 1 pound of weight represents 3600 calories. if you had a bar a day, as I do, it would take you 144days to make a pound's worth of difference to your losses. Meanwhile the bars are lush, and i'm having a lovely time eating them.