Oh, you'll get into ketosis having the bars. It's just that some folks find that bars give them the munchies, so it can be harder to stay on the wagon long enough to get into ketosis.
Hence, it's recommended you don't have them until ketosis is established.
The crunchy bars have around the same number of carbs in as the shakes and soups anyway (that's the peanut, cranberry and mint bars) so if you want bars from Day 1, they're your best choice.
The chewy bars (chocolate, chocolate orange, malt toffee and caramel) appear to have a higher number of carbs. But the additional carbs in those bars are mainly due to stuff called malitol. Malitol is actually fibre, not carbohydrate, but it's always classified as carbohydrate which is why the chewy bars are marked as being higher in carbs. But even that's not the full picture, because some sensitive souls react to malitol as if it is carbohydrate and find that if they have a lot of it, they'll come out of ketosis.
Malitol, if eaten in excess, acts like a laxative - but then it would, cos it's fibre.
That's why only one bar a day is recommended.