Asset Values 5000

Hi,

I have now requirement, Asset value is less then Rs. 5000 , Asset is depreciated 100% on the date of book itself. How to Configure the following requirement.

Now am create 100% depreciation key and assign Asset Master Data , Asset Useful life 1Month . But Its not working?

Its Calculated Only 15 days only . Remaining balance calculated next month only. i need net of booking date 100%.

Thanks

SV