Periods of varying lengths + subjects in minutes per week (Canada)

If your school have periods of varying lengths you can go to Menu Options/Customize the software. Then in Country specific check that you want to input subjects in minutes:

Then you will be able for each lesson to specify how many minutes per week that lesson shall have:

The length of each period is defined in the Period definition dialog:

Note: you still have to provide also the number of lessons per week. So if Math in 6A shall be 150 minutes, then if you specify 3 lessons per week, the software can decide 60+40+50 or 50+50+50.