GetDungeonDifficultyID and PLAYER_DIFFICULTY_CHANGED do they go together?

[A_Nolan]

function FIZ_OnLoad(self)

-- Events monitored by Event Handler
FIZ_Main = self
self:RegisterEvent("ADDON_LOADED")
self:RegisterEvent("VARIABLES_LOADED")
self:RegisterEvent("PLAYER_ENTERING_WORLD")
self:RegisterEvent("PLAYER_LOGIN")
self:RegisterEvent("GUILD_PERK_UPDATE")
self:RegisterEvent("PLAYER_DIFFICULTY_CHANGED")

end

function FIZ_OnEvent(self, event, ...)

local arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12, arg13 = ...
if (event == "ADDON_LOADED") and (arg1 == FIZ_NAME) then

FIZ_Main:UnregisterEvent("ADDON_LOADED")
FIZ_InitStages = FIZ_InitStages + 1
FIZ_Init()

elseif (event == "VARIABLES_LOADED") then

filler

elseif (event == "PLAYER_LOGIN") then

filler

elseif (event == "PLAYER_ENTERING_WORLD") then

filler

--elseif( event == "PLAYER_LEAVING_WORLD" ) then

filler

elseif (event == "UPDATE_FACTION" or

event == "QUEST_COMPLETE" or
event == "QUEST_WATCH_UPDATE") then

filler

elseif ( event == "BAG_UPDATE") then

filler

--elseif ( event == "UNIT_INVENTORY_CHANGED") then

filler

elseif ( event == "BANKFRAME_OPENED") then

filler

elseif ( event == "BANKFRAME_CLOSED") then

filler

elseif ( event == "CHAT_MSG_SKILL") or

filler

elseif ( event == "GUILD_PERK_UPDATE") then

filler

elseif ( event == "PLAYER_DIFFICULTY_CHANGED") then

FIZ_difficultyID = GetDungeonDifficultyID()
if (FIZ_difficultyID == 2) then

FIZ_IsHeroic = true

else

FIZ_IsHeroic = false

end

end

ok the sticky said to enter the entire code so i'v put in the main part. Is PLAYER_DIFFICULTY_CHANGED the correct event to pull when the dungeon difficulty (normal/heroic) is toggled. I have the correct setup to get the difficulty but can't get the thing to fire when i toggle it.