IBM-DM-013: Problems with Element Node, typed-value accessor

Data Model Section 6.2.2 (Element Nodes--Accessors): The dm:typed-value 
accessor, second bullet, says that the typed value is derived from the 
string value and its type in a way that is consistent with schema 
validation. But it also says that, for date/time types, the typed value is 
"the atomic value derived from its tuple representation ...". These 
statements contradict each other. The string value does not contain any 
tuple representation. What property of an element node contains this 
"tuple representation"? Is the typed value derived from the string value, 
or not?