Hi Ruks
Was it you the culprit who lured your client into activating ABCOPA? 
[Just Kidding]
The answer would depend on case-to-case basis. Lets talk about this one.
Your Profit on sale of asset is a non-operating income. So you must not create it as Catg 11 Cost Element.. You should rather have it as 01 and use the settings in ACSET to post the Profit or Loss on sale of asset into the Cost Center / IO / WBSE assigned in the asset master
Every small setting in SAP has a business reason (Like I explained the business reason behind cost element catg).. All we need is to know that business reason, and you would get driven to the correct solution
Rgds
Ajay M