P4310 copy without item cat code defaults

Using the P4310 Add-functionality it's possible to change/add item category codes on purchase order line level. These manual values overwrite the item cat code defaults.

Using the P4310 Copy-functionality it's NOT possible to change/add item category codes on purchase order line level. After leaving the line these manual values were overwritten by the item cat code defaults.

• Changing a copied line
• Changing a copied line and re-change the cat codes manually again
• Adding a new line in the copied order and change the cat codes manually

Is there a possibility to prevent processing the Add- and the Copy-functunality in a different way? From my point of view the P4310 should generally work like it does in the Add-mode.