Unable to book 40mins on Basic.

Hi @Markie 

These are just the default time duration options. You can manually enter 40 minutes as the duration, but the scheduled duration has no actual affect on the meeting. This duration is mainly used when creating calendar events, so that the appropriate block of time is occupied on someone's calendar. 

Hope that helps and please make sure to mark the solution as accepted if this information is what you needed.

Instructor schedules a meeting in Canvas.
Students join the meeting.
Instructor has pre-set a break for the meeting at 30 minutes (or whatever time feels like a good stopping point.)
At the 30-minute mark, the instructor tells students they are taking a 5 minute break, and instructs students to return in 5 min.
The instructor ends the meeting.
When it’s time to return to the meeting, the instructor restarts the same meeting she or he just ended. (Same meeting ID, same calendar invite, etc.)
Students click on the same link they did before.
Everyone is in the same meeting, only it is a new meeting now, with a new 40-min. time limit.

Regards,
J Wick