‘Asset Impairment’ (FA_WEB_ASSET_IMPAIRMENT_FN),

I want to use functionalities ‘Asset Impairment’ (FA_WEB_ASSET_IMPAIRMENT_FN), but I have problem.

I created and loaded the Impairment transaction with the value of Impairment loss equal 10 000. Next, I run the ‘Run depreciation’ program – at last. At the next month, I wanted to reduce  the value of Accumulated Impairment . I wanted to enter Impairment loss = -3 000. I tried  to load this transaction, but I got warning ‘You cannot enter negative value of Impairment Loss’.  

My questions. Why can not I enter a negative value of impairment? How to reduce the accumulated impairment?

Gosia