Smoothing enabled and increased asset useful life

Hi all,

In our business scenario,

Asset Useful life for Computers are increasing from 3 years to 4 years in middle of the fiscal year after enabling/selecting Smoothing option,Asset is already used for 2 years, the remaining depreciation is spreading in next 2 years.

But if we retire the asset in middle of the asset, still asset showing planned depreciation values for the remaining periods in current year, which we do not want.

Once we retire assets, there should not be any planned depreciation in current year.

any suggestions plz...we are on ECC 6.0 without document splitting.

Regards,

Ramakrishna