7.3 and 2.2 - Consistency of terms?

In 7.3 we find the phrase "top level element nodes". In 2.2 we have 
"top-level" elements.

A hyphen or no hyphen?

Also do we need a new term at all?

The term "top level" is not used in XPath 1.0 as far as I recall. The XPath 
1.0 term for "top level element node" would be "document element node".

Since 7.2 already refers to instance data as returning a DOM document would 
it be better to use XPath terminology in a corresponding way?

I appreciate that there is a bit of a fudge as to whether an instance data 
"document" exists or not prior to serialization but introducing a new term 
"top level" seems possibly unhelpful not least since top-level is a 
frequently used in the context of XPath XSLT 1.0 term with a different 
meaning.

If "top level" or "top-level" is to be used then consistent usage would be an 
advantage.

Andrew Watt