It is not overkill since they are not really the same thing. The Planning book walks you through the whole process of deciding what and when to teach, how to plan the terms, etc to create your plan. That’s it. How you record your plans and accomplishments is up to you. So…paper planner or electronic… 😉
The SCMO is where you imput your plan and then use it to mark your progress for the year as you get the lessons done. The advantage is that you can be flexible with SCMO in ways that paper planning is not – you miss something for a day or week and on paper, you have to re-schedule it. In the SCMO, it automatically adjusts to the next scheduled lesson.