The ‘multiple tasks schedule’ does not support recurrence, and I’m not sure if/when it will. Your options are:
1. Add two rows to the grid with the same target computer in each row. Then create a recurring scheduled task for each row.
2. Use the multiple tasks schedule and simply pick the exact dates and times you want the tasks to run instead of using the recurrence option. You can schedule the tasks as far in advance as you would like, so it would not take very long to schedule a couple years or more worth of monthly tasks.
I hope this helps.
-Doug