The script shows the offset from GMT-UTC in standard format through string manipulation.
#include <Date.au3>
ConsoleWrite (_TimeZoneInfo() & @CRLF)
Func _TimeZoneInfo()
$aInfo = _Date_Time_GetTimeZoneInformation()
ConsoleWrite("bias: " & $aInfo[1] & @CRLF)
$hours = $aInfo[1] / 60
If $hours = "0" Then
$hours = "+00:00"
Else
If StringInStr($hours, "-") Then
$hours = StringReplace($hours, "-", "+")
Else
$hours = "-" & $hours
EndIf
If Not StringInStr($hours, ".") Then $hours = $hours & ":00"
$hours = StringReplace($hours, ".5", ":30")
$hours = StringReplace($hours, ".75", ":45")
If StringLen($hours) = 5 Then $hours = StringLeft($hours, 1) & "0" & StringRight($hours, 4)
EndIf
Return ($aInfo[2] & " (GMT" & $hours & ")")
EndFunc ;==>_TimeZoneInfo