In further confirmation of the Time Trials I noted below, and in answer to my further question regarding the Coldain Shawl Zephyr of Brell Effect I performed an additional test today. This is post July 14 Patch which added the timers to spell effects in your buff window.
Since the time of my initial postings and tests I finished the Coldain Shawl Quest and obtained the Shawl. When I cast KEI on myself today with the Shawl equipped and both SCR and SCRM maxxed out the timer said the KEI had 255 Minutes to run.
With a base of 150 Minutes for KEI this shows that the 20% (or total 70%) Extension does apply as 150 x 1.70 = 255.
So for all you out there that want the benefit of the extensions (and the attendant savings in mana costs) I think this shows you can keep on questing and putting your AAExp into SCR and SCRM for the full benefits.
Edited, Fri Jul 16 15:59:10 2004