wrong depreciation calculated on asset

Dear sap experts

As per the use full life changes as per companies act i have changes the depreciation key in the asset class but wrong depreciation calculating for certain asset.

2013 System depreciation calculation was correct but in 2014 when we have changed the depreciation  key as use full system calculated depreciation wrongly i.e around 2684 for month hence in the above bellow screen shot period 8 showing wrong value

Please guide

Details mention bellow

I run the depreciation on 2015 run the depreciation  after assigning the new use full life key on 8th period on 2014 after that there has been no changes in key and life but in 2015 balance is calculated in 4th period.

Thanks and regards,

Prakash