3 January 2007 External T.I. 2006-0180601E5 F - Facturation entre deux sociétés affiliées. -- summary under Subsection 230(1)

Is there a need for written invoicing for management services between two non-arm's length corporations? CRA indicated this is not required under the Act, but invoices remain proof of income tax liability thereunder – and, in this regard, referred to various statements in IC-78-10R4 regarding record retention.