Here's the thing, even if the percentage is 33% on elite, which I don't believe for a second, that 33% is shared with all the named items available for that quest. So Myth Drannor for example, there are 2 variants of every weapon equaling 100, there's the 3-5 named items people want, and all the solar/lunar gems which are about 60ish (estimate) This adds up to be approximately 165. Now you have to divide that .33 (33%) by 165 and that's closer to .002 or .2% for an item you want. That's 2 out of 1000, or 1 out of 500 if you want to reduce it to simplest form. And have you ever opened a chest, got a named item you didn't want, reroll and got no named item? Yeah, that happens more than you'd think. How bout once you get a named item it locks you into a named item category so that next reroll guarantees you a named item.