Yes. This is a lower carbohydrate type diet (it does still include the carbs in fruits and vegetables of course). The 90% number simply means that you choose this type of food most of the time. I don't expect anyone to really tally out how much they eat off the menu and the amount that you are able to depart without regain is a function of your individual physiology.
Having been on this type of diet for about five years now, I find that I always know I can eat grains or potatoes or bread or whatever if I want to. But after choosing not to so often, I don't really care about them that much. I must add that I used to eat huge amounts of sweets, bread and pasta, so that this was a big change. Once again, I am so enjoying all of your questions and conversation. So let me ask all of you a question: Do the maintainers out there ever find that eating grains, breads, potatoes, pasta other starches cause you to gain weight or crave more? Or have you found ways to incorporate them without a problem?