A Conditional Section in QName Declaration..[XHTMLMOD]

Even though I stepped into W3C Membership, I'm a beginner in XML yet.
So I can't deeply understand "XHTML Modularization".

Well, I've got a question as below.

In the Appendix section D.2.1 - Qualified Names sub-modules - , 
there is an example code of conditional section which declares a prefix for a module, 'inventory'.
Here is its code.

<![%Inventory.prefixed; [
<!ENTITY % Inventory.pfx "%Inventory.prefix;:">
]]>
<!ENTITY % Inventory.pfx "">

[XHTMLMOD] says -
"Define a parameter entity MODULE.pfx that is "%MODULE.prefix::" 
when prefixing is enabled, and "" when it is not." 

In this example, initially the value of Inventory.prefixed is assigned for "IGNORE", so it makes sense.
But, How about in the case of "INCLUDE"???
I think the last line of this example is parsed always, so the prefix is configured as default XML namespace 
in the namespace-aware parser.

Hope your kind comments, 

Jin.