Depreciation key change for assets with shift factor

Dear All,

In the current system we have to change depreciation key from percentage to useful life for assets which have shift factor is in use

Depreciation calculation method is straight line as per legal requirements client has to change depreciation calculation method from percentage to useful life

If i change depreciation key for the existed assets from % to useful life then system is not calculating depreciation values equally for the remaining period of the assets where ever shift factor is in use, assets which are not having shift factor has no issue it is calculating depreciation equally

Please suggest what is the reason

Regards,

Upendar Singh