Carry forward leave issue

Hello Friend,

I am doing the carry forward leave quota generation though PT60.

I am new for the Time management,

client is using the negative TM.

Scenario is like ---- PL leave is 30 days for year. leave accrued 2.5 per month.

The maximum leave should be carry forward for the next year should be 15 days.

But when i run the PT60, the system is generating the leave quota 47.5

47.5 = 15 days last year leave quota + 30 days current year leave quotas + 2.5. Jan 2015 month leave

i am unable to understand why system generating more leave quotas then actual.

Please anybody help me how to resolve this issue and give me guide line what confi need to check for the same.

Thanks

Urvashi Chaudhari