Child support cases can be particularly complex
If you have ever experienced complexity in dealing with the Child Support Agency, bear a thought for the Watanabe’s. The difficulty that they faced was that orders had been made by a Federal Magistrate as to the amount of time that the father should spend with the children.
Depending on what interpretation was made of those orders altered the amount of time that the father had with the children, and therefore (presumably substantially) altered the amount of child support that he would have to pay.
The matter made its way from a child support assessment, through the objection process, past the Social Security Appeals Tribunal, from where it then wended its way into the hands of Federal Magistrate Slack in Watanabe and Watanabe.
His Honour ultimately sent the matter back to the Social Secuirty Tribunal as there was an error of law, because neither party had provided the Tribunal with the earlier Federal Magistrate’s reasons for judgment, nor a short transcript of when the matter had been argued again.
His Honour’s reasons are particularly significant because he sets out the law as to how orders are to be interpreted, which has long been a topic of controversy:
In a useful article, Construing Undertakings and Court Orders (2008)
82 ALJ 82, the author John Tarrant, refers to a number of decisions. Mr
Tarrant identifies two lines of authority on the approach to the interpretation
of Court orders.
In Repatriation Commission v Nation (1995)
57 FCR 25, the Full Court of the Federal Court (Beaumont J, with whom Black
CJ and Jenkinson J agreed), said (at 34):
Under the ordinary rules of construction, evidence of surrounding circumstances is admissible to assist in the interpretation of an instrument if the language is ambiguous or susceptible to more than one meaning but not admissible to contradict the language of the instrument when it has a plain meaning.
In his article Mr Tarrant identifies a second line of authority that supports the proposition that the reasons for judgment must be referred to so as to ensure that Court orders are interpreted in the correct context.
He refers to the decisions of Yates Property Corp Pty Ltd v Boland (1998)
89 FCR 78 and Australian Energy Ltd v Lennard Oil NL [No.2] 
2 Qd R 230. In particular, reference is made in the decision of Yates
Property to the remarks of Drummond J (at 78) that it is impermissible, in my
view, as well as being quite unrealistic, to attempt to read, that is, to
understand, an order in isolation from the context of the reasons for it being
I do not consider it necessary to resolve the apparent difference in
the lines of authority on the use of extrinsic material in the interpretation of
orders. In this matter I consider that the orders are not clear and unambiguous
and the SSAT would have been (had they known of the existence of the material)
entitled to not only rely upon extrinsic evidence but, as a matter of law,
should have relied upon extrinsic material if that material clarified the
intention or intended effect of the orders.
As to what additional material can be referred to in interpreting Court orders:
In Owston Nominees No 2 Pty Ltd v Branir Pty Ltd  FCA
629; (2003) 129 FCR 558 at 569, Allsop J, in considering the exercise of power to deal with entered orders said:
the reasons, the pleadings and, if necessary, the evidence and how the case was conducted may be relevant extrinsic evidence.
In Athens v Randwick City Council  NSWCA
317; (2005) 64 NSWLR 58, Santow JA said that if an order was ambiguous and the ambiguity could not be resolved by reference to the judgment then resort may be had to the proceedings and in particular the pleadings, which provide an interpretive
It would frequently be the case in family disputes that the matter
is resolved with the consent of the parties without hearing and hence there
would unlikely be such material. Whilst the subjective intention of the parties
would not be relevant to the construction of the orders, I consider evidence of
the common intention of the parties at the time the orders were made would be
admissible and in that regard evidence about the manner in which the parties
have interpreted the orders may be relevant extrinsic evidence as to the common
intention of the parties.