Time management is definitely very important in the four walls of a classroom. From the introduction to the presentation onto the interactive sessions of the class each sessions supposed to have a time allocated in order to manage the time given and you have duely clarified that aspect in your post. To achieve this aim, what needs to be done is what you called "Careful Planning". And with this, time management becomes very easy to be achieved.

Definitely why teaching in a classroom they are mainly on various challenges that can be present to disrupt the class activities, but surely, there are ways to handle and manage these challenges. Mainly managing challenges in class will have to be done by immediately addressing the issue, personal attention and interaction as well as being focused and vigilant.

Your lesson plan gives a good view of what a standard one should look like with the introduction of shared time for each stages of teaching to manage the time frame of 20 minutes.

Thanks for sharing