clarification vxml 2.0

I have been putting together a course to teach VXML 2.0, but have found
a few inconsistencies in the spec, and would like these cleared up, if
possible. 
1) With the builtin grammar type "boolean", what is returned, is it the
Boolean value true/false, or is it the string 'true'/'false' ?
this is very important when comparing the returned result to see if
caller confirmed or not. 
I copied the following boxed explanation from the spec, but it seems
ambiguous to me. 'The result is [true/false]. The value will be
submitted as the string ["true"/"false"] ' - what does that mean? 
The implementation of VXML that I've been using, took it to mean that
the grammar returns the string 'true'/'false' as the return value of the
grammar. Of course, this took some recoding of my apps when I realized
this, and it didn't seem right, so more than just myself has been
confused on this point.       
 
http://www.w3.org/TR/2004/REC-voicexml20-20040316/#dmlABuiltins
The value returned by a builtin type can be read out using the <say-as>
element. VoiceXML extends <say-as> in [SSML]
<http://www.w3.org/TR/2004/REC-voicexml20-20040316/#ref_SSML#ref_SSML>
by adding 'interpret-as' values corresponding to each builtin type.
These values take the form "vxml:<type>" where type is a builtin type.
The precise rendering of builtin types is platform-specific and will
vary by language.
The builtin types are:

boolean
Inputs include affirmative and negative phrases appropriate to the
current language. DTMF 1 is affirmative and 2 is negative. The result is
ECMAScript true for affirmative or false for negative. The value will be
submitted as the string "true" or the string "false". If the field value
is subsequently used in <say-as> with the interpret-as value
"vxml:boolean", it will be spoken as an affirmative or negative phrase
appropriate to the current language.
 
 
2) With the <say-as interpret-as="."> element, what value should be used
for interpret-as?
In appendix P of the spec, it says use "vxml:type"  where type=builtin
grammar type. 
Other areas of the spec, have examples of interpret-as="type" where
again type is a grammar type, but they don't use the "vxml:type"
(hence omitting the "vxml:" prefix). Which of these is proper/correct?
Please make the spec more consistent in its examples.
 
 
3) Furthermore, where are the values for the format attribute of say-as
defined?
 
 
Thanks, 
Janine Graves
 
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Marblehead, MA 01945
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