prep time versus teach time

So it took ninety minutes to put his sub plans together. Let's presume that he teaches in the Block and therefore his class is ninety minutes long.


You know what, let's presume that he doesn't teach in the Block and his class period is, oh, about an hour.

Either way, isn't it fair to presume that planning for a period should be equal to, if not greater than, direct instructional time?

When (if) I go back to the classroom, I'm definitely following this model: