[F&O] IBM-FO-035: Problems with fn:number

(IBM-FO-035): Section 14.1.4 (fn:number): The summary paragraph says that 
if the context item is not a node, NaN is returned. The third paragraph 
seems to contradict this by saying that if the context node is atomic, its 
value is converted to xs:double. On closer reading the confusion only 
increases: how can a node be atomic? Then the fourth paragraph says that 
in the case of a node with an atomic type, its "value" is converted to 
xs:double. Does this refer to the node's typed value or its string value?

--Don Chamberlin