BPP Revision kit - GW on acquisition

Hi, There is a question in BPP I would need some explanation about. C Co acquired 70% of B Co's 100K $1 ordinary shares for $800K when the RE of B Co were $570K. B Co also has an internally generated customer list which has been valued at $90K. The NCI in B Co has a FV of $220K at the date of acquisition. What was the goodwill arising on acquisition? The answer given in the book is $350K, i.e.: Consideration transferred 800 NCI @ acquisition 220 Net Assets (RE + Shares) 670 Goodwill 350 Why the customer lists FV is not included in the net assets of the acquired entity? It is an identifiable asset, it has a valuation (cost can be measured) and we could expect future economic benefits. It was my understanding, that if it was e.g. a brand value instead we would include it into total of net assets as identified and measured intangible, why is it different for customer lists? Thanks a lot in advance!