- We have got about 50 licenses of Office 2013 home&business under the same Microsoft-account.
- The product-keys, that are displayed at office.com/Setup "Install from a disk - view your product key" are different to the product-keys on the product-key-cards
- I installed any of the 50 Office-licenses from office.com/Setup and tryed to change the product-key
- There is no option to change the product-key of Office 2013 home&business in the control-panel "program and features" or in Word/Excel "file - account"
- The commandline-Program "cscript ospp.vbs /inpkey:9NJHW-...."
displays the following error:
Microsoft (R) Windows Script Host, Version 5.8
Copyright (C) Microsoft Corporation 1996-2001. Alle Rechte vorbehalten.
---Processing--------------------------
---------------------------------------
ERROR CODE: 0xC004F069
ERROR DESCRIPTION: The Software Licensing Service reported that the product SKU
is not found.
---------------------------------------
---Exiting-----------------------------
So Microsoft - is there a way to install Office 2013 home&business with the correct product-key, if I needed to reinstall one of our computers?

Have you tried the steps below? It doesn't give you the option to change the product key until the very last steps.
Open Control Panel
Open Programs and Features
Highlight Microsoft Office 2013
Click Change
Select Online Repair
Click Repair
Click Repair in the pop up box
After it is done repairing
Close the Control Panel
Down in the system tray should be an Office 2013 logo. When you click on it, I says "Office is installing in the background (xx%) You can use your programs now, but please don't go offline or restart your computer."
Wait for the install to complete and this box disappears.
Start any Office program
A "Activate Office" box will pop up
Midway down Click "Enter a product key instead"
Enter your new product key
Click Install.
To check that it was done correctly, Open any Office program. Go to File. Click Account. In the window to the right it should say "Product Activated"