Hi Sridevi, Sakar,
Thanks for your input.
I will answer by giving an example:
Asset acquired in May 2013.
Book (IFRS) depreciation starts in the month of acquisition. i.e. in May 2013. "Depreciation start date" in the last Tab of asset master is 1.05.2013.
Tax (EVL) depreciation is calculated for the whole year 2013 (from January to December 2013) - "Depreciation start date" in the last Tab of asset master is 1.01.2013.
For the normal asset everything works. Period Control in Depreciation Key for Tax area is 06/06/06/06 where 06 means: "At the start of the year".
The problem is only for the Special Asset indicated in OAKB. With the same Depreciation Key (06/06/06/06) depreciation of this special asset should start in the year of sales/scrap, unfortunately it starts a year later.
Example: original asset is sold in April 2014. System calculates the value to be still depreciated in Tax area (by deducting Sales price from Net Book Value). We call this new value as the NEW NBV. In the month of sales (April 2014) system reverses depreciation posted in Tax Area for January-March 2014. And should plan depreciation of NEW NBV from January 2014. But this New NBV is placed in the "Write-up" column on the Comparison Tab of asset master and depreciation is planned from 1.01.2015 (i.e. one year leater) 
Thank you for any advise.
Regards
Jolanta