PCR for sick Leave calculation

Hi Gurus,

I got a new requirement from client where in we have two Absence quotas of Sick Leaves one is Sick Leave and another one is Sick Leave Carryover,

Everymonth, 1 sick leave will be accured. And per annum there will be 12 sick leave.  So what ever is remained will be carryover to the next year.

So in the next year, the total number of Sick Leave + Sick leave carryover should not be more than 15, if the total is 15 then the sick leave will stop accrue for that month until employee uses some sick leave. if the total is less than 15 only then the sick leave will start accrue.

Please help me in designing this PCR.

Thanks and Regards,

Haris.