Atkins says that a person can stay on Induction as long as they feel well.
However, there are some points to think about. If you stay at 20 grams of carbs, your body will get used to that and become very efficient at operating at that carb level. Should your loss slow or even stop, you have nowhere to go. If you increase the carbs as recommended in On-going Weight Loss (5 grams per week), then if you stall, you can decrease the carbs or go right back to Induction to get it started again.
By increasing as in the book, you also will find your own carb level at which you lose, and to which you will return later if you should gain a few pounds back.
Some people actually lose BETTER at a higher carb level. This is why many people do better on Protein Power Plan or Carb Addicts. It takes experimentation to learn which level is best for you.
Compared to many people here (look at my stats) you don't have a huge amount to lose. That means you are closer to your goal than I am. The last 10 - 20 pounds come off slowly and that isn't bad. You get that time to really become accustomed to eating low carb and changing your metabolism.
So consider following the advice in the book first. We are all impatient and want to lose quickly but it isn't always the best idea.