Hi Renjith,
When you created this maintenance plan, since call date is today date, system should display it as Save to call.
This is how the scheduling will work. Above screenshot call date is 06.04.2016, which is today. There is no setting in SPRO.
May be check a task list which has only month not weeks and see how it works. To make sure system schedules correctly. Then the issue is because of weeks and 90% call horizon.
Regards
Terence