Related Party Transaction

[JJK]

Hi:

  An US C Corp (Parent) is thinking of allocation some variable cost from USA to a New Zealand subsidiary.   My understanding is this will be a related party transaction, correct?  If yes

    1.  What factors should be considered when allocating cost to sub?

     2. Is Excel file demonstrating allocation an adequate document? what else should I have to avoid any audit?

       3. What tax rule applies and what tax form should I use to report this?

     Thank you.