Legendary Cube rates on weapons too high?

Yeah I have used around 1,000 regular cubes and turned dozens and dozens of items unique since they came out the summer of '10. I have never seen cube rates from Unique to Legendary like I have using the new super cubes. Unless you are lucky within 10 cubes, it is taking between 50 and 90 cubes to get a single item legendary. So I would guess less than a 5% chance to get an item Legendary. More like 2-3% chance. Not quite sure if this is a bug, or if this is the intended functionality. If it is, I will largely ignore the legendary tier then as will I guess most of the population.