Dividends from subsidiary at mid-year acquisition

Can you help me with accounting treatment for dividends recived from subsidiary at mid-year acquisition?
For example, in dec-09 question, On 1 April 2009 Pandar purchased 80% of the equity shares in Salva (CSOFP date – 30 September 2006, post-acqn period = 6 month), On 26 September 2009 Slava paid the dividends $8000 (80% – $6400). In answer all the dividends reduce Investment income. Is it right? I thought that part of them refers to pre-acqn period and must reduce investments in subs.