Krzysztof is correct, that is the periodization of the L3 plan.
We do recommend that no individual formal plan be longer than 24 weeks, and that recommendation is reflected in our plans. It’s an extension of our rejection that “more is always better.”
This doesn’t mean that the best athletes don’t train year-round. An annual training plan should include 45+ weeks of training for peak performance, but the year should be split up into distinct seasons: 2 or 3 formal plans separated by deliberate rest and recovery. More than 24 weeks at a time of non-stop training will, unequivocally, lead to overtraining. It may take 2, 3, 4 years, but there is a debt that is built up (particularly in red blood cell destruction) that must be re-paid every 6 months or so through rest.
Therefore, we encourage long-term, annual planning. But if your event is more than 6 months in the future, split that period into two seasons. In your case, consider the free Maintenance plan to tie you over until January, take 1-2 weeks off, then start your formal IM plan.
Commercially, I’m confident that we could make more money if we offered 8+ month IM plans. We could charge more for the plan, and perhaps more people are interested in starting a plan for a race almost a year away. We just know it is not in the athlete’s best long-term interest.
Finally, our position is supported by Bompa’s Periodization: Theory and Methodology of Training and Friel’s Triathlete’s Training Bible which both also recommend the ~6-month limit.