NGUI simply sends the OnTooltip notification. What you do inside this tooltip is up to you. If you want it to watch some object and update the values inside based on some changing data, then you will need to write precisely that logic in your script rather than simply calling UITooltip.ShowText only once. Keep in mind, you can call UITooltip.ShowText multiple times in a row if you want. Also note that the entire UITooltip class is an example that can be modified to fit your needs. For Windward I am using a custom tooltip type for example, as I need to use one label to display the item's name, and another label to display the stats.