Thanks Vinay.
If you are creating sub assets usually some of the values are inherited from the main assets. Probably, this could be preventing you from updating the cost center on sub asset numbers.
Please check if you are able to change them manually on AS12 or they are grayed out:
As you said if it is working in one system, I would expect to work the same in another system, unless the configuration is different or something wrong in the file:
The other option now available is:
a) if there are only 12, you can change them manually
b) if there are many, please write a quick LSMW
May be the following blog would be handy for you: