REAL %SubTimesMono(
   TIME in TimeA,
   TIME in TimeB,
 )

 ; =================================================================
 ;  Slovakia (country for this example)
 ;  Time zone is UTC+1.
 ;  There are summer [A] and winter [B] time (with time shifts).
 ;  Summer time is from 29th March 2009 to 24th October 2009.
 ;  A3:00:00 is changed to B2:00:00 on Sunday (25th October 2009).
 ; =================================================================
 
 BEGIN
 
  TIME _timeA
  TIME _timeB
  TIME _baseTime
 
  REAL _subMono1
  REAL _subMono2
 
  ; UTC 00:30:00 25.10.2009
  _timeA := %StrToTimeEx("A2:30:00 25.10.2009", "hh:mi:ss dd-mm-rrrr")
  ; UTC 01:30:00 25.10.2009
  _timeB := %StrToTimeEx("B2:30:00 25.10.2009", "hh:mi:ss dd-mm-rrrr")
  ; UTC 23:30:00 24.10.2009
  _baseTime := %StrToTimeEx("01:30:00 25.10.2009", "hh:mi:ss dd-mm-rrrr")
 
  ; difference 1 hour(s) (3600 seconds)
  _subMono1 := %SubTimesMono(_timeA, _baseTime)
  ; difference 2 hour(s) (7200 seconds)
  _subMono2 := %SubTimesMono(_timeB, _baseTime)
 
 END