Oleg,
We don’t like more than 26 weeks of non-stop formal training without some sort of break. A minimum 1-2 week break is recommended between plans. However, you will just be using 4 weeks of the Maintenance plan between now and the start of your 22-week IM, which puts you at that 26 week limit. In that case, just transition directly from Week 4 of the Maintenance plan to Week 1 of the IM plan.
If you were doing regular, formal training before you started the Maintenance plan, that would extend you beyond the 26-week threshold, and then I would take a 1-week break before the IM plan.
David