Regarding maintenance plan schedule

Hi Experts,

          I have created one time based single cycle maintenance plan.1 plan is missing after schedule.Scenario is given below.

Plan                        Time base single cycle

cycle/unit                 2 months

Call Horizon              90%

Schedule period        2Years

Scheduling indicator  Time-Key date

Cycle start date         Same date as maint plan created

       When i schedule in ip10 i am getting only 11 plans,intead of 12 plans.

Regards

Prashanth