[F&O] IBM-FO-024: Apply implicit timezone rule uniformly

(IBM-FO-024): In Section 9.3, Comparison of Duration, Date, and Time 
Values, the last paragraph says "If the timezone part is (), the implicit 
timezone is used to adjust the normalized value as necessary." I am 
wondering why this rule is found only in the description of the comparison 
functions and not other functions that operate on dates and times. Section 
9.4 (Component Extraction Functions) does not state such a rule. Section 
9.7, which contains arithmetic functions on dates and times, says "If any 
argument ... does not contain an explicit timezone, then ... an implicit 
timezone ... is assumed to be present." This rule does not say anything 
about adjusting the normalized value. I find it confusing that the rule 
dealing with implicit timezones is stated in different and possibly 
conflicting ways in Sections 9.3 and 9.7, and missing in Section 9.4.

--Don Chamberlin