Having to grind finer is usually a symptom of using older roasted beans. What they are referring to from "aged beans" is using aged green beans in their roast. Aged green beans are said to have more depth and sweetness.
Maybe try getting some freshly roasted beans (4-7 days post roast) off them and try again. 6 week old coffee isnt going to give you a good result. Typically coffee is best consumed within 2 weeks after roasting.
BTW what is your setup?