Question on normal semantic declarations in collada document

I was wondering why in the maya exporter the normals semantics are declared in different ways. As an example I have seen the following where the normals are under the vertices element:

<vertices id=“pSphere-lib-Vertex”>
<input semantic=“POSITION” source="#pSphere-lib-Position"/>
<input semantic=“NORMAL” source="#pSphere-lib-Normal"/>
</vertices>
<polygons material=“blinn1” count=“760”>
<input semantic=“VERTEX” offset=“0"source=”#pSphere-lib-Vertex"/>

But at other times I have seen the following (often in the same document) where the normals is in its own input semantic - which seems to be the way the max exporter implementation writes out collada xml files also.

<vertices id=“pSphere-lib-Vertex”>
<input semantic=“POSITION” source="#pSphere-lib-Position"/>
</vertices>
<polygons material=“blinn1” count=“760”>
<input semantic=“VERTEX” offset=“0"source=”#pSphere-lib-Vertex"/>
<input semantic=“NORMAL” source="#pSphere-lib-Normal"/>

Both forms are perfectly valid and you should write your importer to handle both. This was discussed about half way down the second page of this thread. This has confused people in the past and it’d be nice if the spec were a little more explicit in explaining that this is legal.