Depreciation calculation based on which date

Hi ALL,

We have depreciation key configured with period control 03 (Pro rata at mid period).In Asset master , ordinary depreciation date is mentioned as 01/04/2013 while Capitalised On date is mentioned as 30/04/2013.

Depreciation is calculated for the full month & we would like it to be calculated for half month as asset capitalised date is 30/4/2013.

Kindly let me know the check points so that system calculates depreciation for half month if capitalised date is mentioned any date after mid of month.

Thanks

Kishore Jain