Asset Dep calculation issue

Hi Sap Friends,

Here i have one issue regarding Asset Depreciation calculation.

If asset is acquired in Current year system is calculating depreciation for whole period.

But if the Asset is Acquired in last year and i am again acquiring some amount in the same asset code deprecation will be calculated as per the the configuration done.

If Acq date is between 1 to 15 the dep. calculated should be posted in that same month But if Acq is done between 16 to 31 the Dep. should be posted in the next period like if it acquired on 17th Jan Dep should calculation should start for Feb.

All this above functions are working fine for Previous year purchased asset but not for current year purchased asset...

Help needed can anyone let me know is there any specific settings for this.......

Thanks & Regards

Prashant