WoWInterface - 10.0.2, GetItem() and Comparison tooltips.

Greetings,

I am attempting to update my addon to work with the new tooltip system introduced with the latest patch. I was able to get it to mostly work by replacing all of the old hookscript lines with the new TooltipDataProcessor.AddTooltipPostCall function.

For the most part, this allows my code to run properly. The only issue that seems to remain is when an item comparison tooltip is on the screen, the code does not run and errors out. The error I am getting is stating that the GetItem() call is a nil value.
Code:
    5x Interface/AddOns/ConvertRatings/ConvertRatings.lua:296: attempt to call method 'GetItem' (a nil value)

    [string "@Interface/AddOns/ConvertRatings/ConvertRatings.lua"]:296: in function <Interface/AddOns/ConvertRatings/ConvertRatings.lua:228>

    [string "=(tail call)"]: ?

    [string "=[C]"]: in function `securecallfunction'

    [string "@Interface/SharedXML/Tooltip/TooltipDataHandler.lua"]:60: in  function <Interface/SharedXML/Tooltip/TooltipDataHandler.lua:55>

    [string "@Interface/SharedXML/Tooltip/TooltipDataHandler.lua"]:80: in function <Interface/SharedXML/Tooltip/TooltipDataHandler.lua:76>

    [string "@Interface/SharedXML/Tooltip/TooltipDataHandler.lua"]:116: in function <Interface/SharedXML/Tooltip/TooltipDataHandler.lua:106>

    [string "=[C]"]: in function `SetAttribute'

    [string "@Interface/SharedXML/Tooltip/TooltipDataHandler.lua"]:141: in function <Interface/SharedXML/Tooltip/TooltipDataHandler.lua:134>

    [string "@Interface/SharedXML/Tooltip/TooltipDataHandler.lua"]:282: in function <Interface/SharedXML/Tooltip/TooltipDataHandler.lua:240>

    [string "=[C]"]: in function `securecallfunction'

    [string "@Interface/SharedXML/Tooltip/TooltipDataHandler.lua"]:237: in function `ProcessInfo'

    [string "@Interface/SharedXML/Tooltip/TooltipComparisonManager.lua"]:249: in function `SetItemTooltip'

    ...

    [string "@Interface/SharedXML/Tooltip/TooltipDataRules.lua"]:161: in function `func'

    [string "@Interface/SharedXML/Tooltip/TooltipDataHandler.lua"]:49: in function <Interface/SharedXML/Tooltip/TooltipDataHandler.lua:44>

    [string "@Interface/SharedXML/Tooltip/TooltipDataHandler.lua"]:71: in function <Interface/SharedXML/Tooltip/TooltipDataHandler.lua:67>

    [string "@Interface/SharedXML/Tooltip/TooltipDataHandler.lua"]:135: in function <Interface/SharedXML/Tooltip/TooltipDataHandler.lua:134>

    [string "@Interface/SharedXML/Tooltip/TooltipDataHandler.lua"]:282: in function <Interface/SharedXML/Tooltip/TooltipDataHandler.lua:240>

    [string "=[C]"]: in function `securecallfunction'

    [string "@Interface/SharedXML/Tooltip/TooltipDataHandler.lua"]:237: in function <Interface/SharedXML/Tooltip/TooltipDataHandler.lua:236>

    [string "=(tail call)"]: ?

    [string "@Interface/FrameXML/PaperDollFrame.lua"]:1738: in function `UpdateTooltip'

    [string "@Interface/FrameXML/GameTooltip.lua"]:498: in function      <Interface/FrameXML/GameTooltip.lua:491>



    Locals:

    self = ShoppingTooltip1 {

    0 = <userdata>

    SetQuestLogRewardSpell = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    SetQuestPartyProgress = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    ProcessLineData = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:303

    SetPvpTalent = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    SetExistingSocketGem = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    SetHyperlink = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    SetUnit = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    SetAzeriteEssence = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    SetVoidDepositItem = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    SetVoidWithdrawalItem = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    SetInfoBackdropStyle = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:338

    SetSocketGem = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    SetLootCurrency = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    SetSlottedKeystone = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    SetItemInteractionItem = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    SetLootItem = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    SetOwnedItemByID = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    SetQuestLogSpecialItem = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    SetRecipeReagentItem = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    SetBuybackItem = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    hasMoney = 1

    SetWeeklyReward = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    SetMerchantItem = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    SetPvpBrawl = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    shownMoneyFrames = 1

    BottomOverlay = Texture {

    }

    SetSpellByID = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    numMoneyFrames = 1

    SetSocketedRelic = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    ProcessInfo = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:236

    ProcessLines = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:293

    NineSlice = Frame {

    }

    SetInventoryItem = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    info = <table> {

    }

    updateTooltipTimer = 0.200000

    SetLootRollItem = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    InternalProcessInfo = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:240

    SetPossession = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    SetUnitDebuffByAuraInstanceID = <function> defined  @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    SetBagItem = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    TextRight1 = ShoppingTooltip1TextRight1 {

    }

    SetAction = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    SetLineDataAttribute = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:232

    SetAchievementByID = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    SetInventoryItemByID = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    SetQuestCurrency = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    SetCurrencyByID = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    SetQuestLogCurrency = <function> defined @Interface/SharedXML/Tooltip/TooltipDataHandler.lua:444

    SetBagItemChild = <function> defined @
Link to full code
https://github.com/mynian/ConvertRat...ertRatings.lua