[Rainrider]

You are right, Phanx.

Wouldn't it be better to just set element.__max = 5 in the ClassIcons' Enable function and not individually in ClassPowerEnable? This way oUF will pick the correct max values on it's initial update and inform the user about the change through PostUpdate.

@@ -155,11 +155,10 @@ do
 			DARK_FORCE = true,
 		}
 
 		ClassPowerEnable = function(self)
 			local element = self.ClassIcons
-			element.__max = 4
 
 			self:RegisterEvent('UNIT_DISPLAYPOWER', Update)
 			self:RegisterEvent('UNIT_POWER_FREQUENT', Update)
 		end
 
@@ -173,11 +172,10 @@ do
 			HOLY_POWER = true,
 		}
 
 		ClassPowerEnable = function(self)
 			local element = self.ClassIcons
-			element.__max = HOLY_POWER_FULL
 
 			self:RegisterEvent('UNIT_DISPLAYPOWER', Update)
 			self:RegisterEvent('UNIT_POWER', Update)
 		end
 
@@ -192,11 +190,10 @@ do
 		}
 		RequireSpec = SPEC_PRIEST_SHADOW
 
 		ClassPowerEnable = function(self)
 			local element = self.ClassIcons
-			element.__max = PRIEST_BAR_NUM_ORBS
 
 			self:RegisterEvent('UNIT_DISPLAYPOWER', Update)
 			self:RegisterEvent('UNIT_POWER_FREQUENT', Update)
 		end
 
@@ -211,11 +208,10 @@ do
 		}
 		RequireSpell = WARLOCK_SOULBURN
 
 		ClassPowerEnable = function(self)
 			local element = self.ClassIcons
-			element.__max = 3
 
 			self:RegisterEvent('UNIT_DISPLAYPOWER', Update)
 			self:RegisterEvent('UNIT_POWER_FREQUENT', Update)
 		end
 
@@ -229,10 +225,11 @@ end
 local Enable = function(self, unit)
 	local element = self.ClassIcons
 	if(not element) then return end
 
 	element.__owner = self
+	element.__max = 5
 	element.ForceUpdate = ForceUpdate
 
 	if(ClassPowerEnable) then
 		if(PlayerClass == 'PRIEST') then
 			self:RegisterEvent('PLAYER_TALENT_UPDATE', Visibility, true)

I could push this to oUF's github repo if you think it would be a better way.