Program: 165704
Project: 165704
Buggy source:
@Override @SideOnly(Side.CLIENT) public List<String> getWailaBody(ItemStack itemStack,List<String> currenttip,IWailaDataAccessor accessor,IWailaConfigHandler config){
  super.getWailaBody(itemStack,currenttip,accessor,config);
  TileEntity tileEntity=accessor.getTileEntity();
  if (tileEntity instanceof PowerCellTileEntity) {
    PowerCellTileEntity powerCellTileEntity=(PowerCellTileEntity)tileEntity;
    int id=powerCellTileEntity.getNetworkId();
    if (Keyboard.isKeyDown(Keyboard.KEY_LSHIFT) || Keyboard.isKeyDown(Keyboard.KEY_RSHIFT)) {
      if (id != -1) {
        currenttip.add(TextFormatting.GREEN + "String_Node_Str" + new DecimalFormat("String_Node_Str").format(id));
      }
 else {
        currenttip.add(TextFormatting.GREEN + "String_Node_Str");
      }
    }
    if (System.currentTimeMillis() - lastTime > 250) {
      lastTime=System.currentTimeMillis();
      RFToolsMessages.INSTANCE.sendToServer(new PacketGetInfoFromServer(RFTools.MODID,new PowerCellInfoPacketServer(powerCellTileEntity)));
    }
    int total=(PowerCellInfoPacketClient.tooltipBlocks - PowerCellInfoPacketClient.tooltipAdvancedBlocks - PowerCellInfoPacketClient.tooltipSimpleBlocks) * PowerCellConfiguration.rfPerNormalCell;
    total+=PowerCellInfoPacketClient.tooltipAdvancedBlocks * PowerCellConfiguration.rfPerNormalCell * advancedFactor;
    total+=PowerCellInfoPacketClient.tooltipSimpleBlocks * PowerCellConfiguration.rfPerNormalCell / PowerCellConfiguration.simpleFactor;
    currenttip.add(TextFormatting.GREEN + "String_Node_Str" + PowerCellInfoPacketClient.tooltipEnergy+ "String_Node_Str"+ total+ "String_Node_Str"+ PowerCellInfoPacketClient.tooltipRfPerTick+ "String_Node_Str");
    PowerCellTileEntity.Mode mode=powerCellTileEntity.getMode(accessor.getSide());
    if (mode == PowerCellTileEntity.Mode.MODE_INPUT) {
      currenttip.add(TextFormatting.YELLOW + "String_Node_Str");
    }
 else     if (mode == PowerCellTileEntity.Mode.MODE_OUTPUT) {
      int cost=(int)((PowerCellInfoPacketClient.tooltipCostFactor - 1.0f) * 1000.0f);
      currenttip.add(TextFormatting.YELLOW + "String_Node_Str" + cost / 10 + "String_Node_Str" + cost % 10 + "String_Node_Str");
    }
  }
  return currenttip;
}

Fixed version (ground truth):
@Override @SideOnly(Side.CLIENT) public List<String> getWailaBody(ItemStack itemStack,List<String> currenttip,IWailaDataAccessor accessor,IWailaConfigHandler config){
  super.getWailaBody(itemStack,currenttip,accessor,config);
  TileEntity tileEntity=accessor.getTileEntity();
  if (tileEntity instanceof PowerCellTileEntity) {
    PowerCellTileEntity powerCellTileEntity=(PowerCellTileEntity)tileEntity;
    int id=powerCellTileEntity.getNetworkId();
    if (Keyboard.isKeyDown(Keyboard.KEY_LSHIFT) || Keyboard.isKeyDown(Keyboard.KEY_RSHIFT)) {
      if (id != -1) {
        currenttip.add(TextFormatting.GREEN + "String_Node_Str" + new DecimalFormat("String_Node_Str").format(id));
      }
 else {
        currenttip.add(TextFormatting.GREEN + "String_Node_Str");
      }
    }
    if (System.currentTimeMillis() - lastTime > 250) {
      lastTime=System.currentTimeMillis();
      RFToolsMessages.INSTANCE.sendToServer(new PacketGetInfoFromServer(RFTools.MODID,new PowerCellInfoPacketServer(powerCellTileEntity)));
    }
    long total=(PowerCellInfoPacketClient.tooltipBlocks - PowerCellInfoPacketClient.tooltipAdvancedBlocks - (long)PowerCellInfoPacketClient.tooltipSimpleBlocks) * PowerCellConfiguration.rfPerNormalCell;
    total+=(long)PowerCellInfoPacketClient.tooltipAdvancedBlocks * PowerCellConfiguration.rfPerNormalCell * advancedFactor;
    total+=(long)PowerCellInfoPacketClient.tooltipSimpleBlocks * PowerCellConfiguration.rfPerNormalCell / PowerCellConfiguration.simpleFactor;
    if (total > 2000000000) {
      total=2000000000;
    }
    currenttip.add(TextFormatting.GREEN + "String_Node_Str" + PowerCellInfoPacketClient.tooltipEnergy+ "String_Node_Str"+ total+ "String_Node_Str"+ PowerCellInfoPacketClient.tooltipRfPerTick+ "String_Node_Str");
    PowerCellTileEntity.Mode mode=powerCellTileEntity.getMode(accessor.getSide());
    if (mode == PowerCellTileEntity.Mode.MODE_INPUT) {
      currenttip.add(TextFormatting.YELLOW + "String_Node_Str");
    }
 else     if (mode == PowerCellTileEntity.Mode.MODE_OUTPUT) {
      int cost=(int)((PowerCellInfoPacketClient.tooltipCostFactor - 1.0f) * 1000.0f);
      currenttip.add(TextFormatting.YELLOW + "String_Node_Str" + cost / 10 + "String_Node_Str" + cost % 10 + "String_Node_Str");
    }
  }
  return currenttip;
}