Merge entries / keep old computer ID

I need OCS to merge inventoried machines if the serialnumber and model are equal. So far it works. But my problem is that the new entry gets a new Computer ID. I need the system to keep the old ID.

For example: I have an inventoried machine with the ID 100. The machine gets a reinstallation and the OCS Agent is installed again. The new entry gets the next available ID and ID 100 is deleted, but I need the machine to keep ID 100.

Any idea where I can configure that? At AUTO_DUPLICATE_LVL "Serial" and "Model" are checked.
OCS Version: 2.1.2

Thanks!

Julien