Quick question about Enrage and Improved Enrage

Hey all, I've been searching around the web and forums and havn't found a definitive answer. Here's my question:
Does Improved Enrage (2/2) add 10 rage to the total rage given by enrage, or does it only give 10 rage instantly, and then another 10 rage (instead of 20) over the duration of Enrage?
If you need any clarification, please feel free to ask and I'll rephrase the question.
Thanks.
Does Improved Enrage (2/2) add 10 rage to the total rage given by enrage, or does it only give 10 rage instantly, and then another 10 rage (instead of 20) over the duration of Enrage?
If you need any clarification, please feel free to ask and I'll rephrase the question.
Thanks.