Quest about remove 'sell price' part from tooltip

[devilArt]

I use following codes to remove 'sell price' line from tooltip
Now 'sell price' line is gone
but still there is a gap in the tooltip

function TOOLTIP:RemoveMoneyLine()
  if not self.shownMoneyFrames then return end
  GameTooltip_ClearMoney(self)
end
GameTooltip:HookScript('OnTooltipSetItem', TOOLTIP.RemoveMoneyLine)

So I checked blizz source code

function SetTooltipMoney(frame, money, type, prefixText, suffixText)
    GameTooltip_AddBlankLinesToTooltip(frame, 1);
    ... more code ...
end

Blizz insert a blank line into 'sell price' part, and GameTooltip_ClearMoney(self) cant remove it
then I stuck here, any solutions?