Change purchase amount in asset .Asset is link with PO with another Amount

Can anyone help me please?
I have created a purchase order where i have brought a laptop of Rs 15000.I have also created purchase receipt from the submited Purchase order.An Asset (laptop HP) created automatically on the system with the purchase cost of Rs 15000.

Later i have to create a purchase invoice to include freight cost and other cost ((Rs 1000)related to this asset.
Is there a way how can i include that RS 1000 (other cost) to the asset and then run depreciation with Rs 16000.
I have try to include Rs 16000 in asset purchase cost instead of Rs 15000.This message is displayed: