Diagnosis
You are changing the control indicator so that depreciation will becalculated at main asset number level.

System Response
At the moment the function 'Dep. at MainAssrNo. is not active.
You can make this change. However, it will effect all the assets youcreate in the future in this asset class.
Assets already defined will not be effected. If you want them to be,you must perform a mass change for all the assets.
Instead of changing the control to calculating depreciation at mainasset number, you should consider creating a new asset class.