Enchating Theory!Follow

One day, i was on my alt Selling enchants when a level 70 mage, who is Maxxed Enchanting level. He whispered me and explained what he was doing. He told me to make 10 Black Mageweave Shoulders. so i made 10, deciding to following his instructions. When i made them, he said to D/E 1 of them. He predicted i would get X Greater Nether Essence. So i D/E it and i got Greater Nether Essence. He said to repeat that and that i would get X Greater Nether Essence again. So i D/E it and i got Greter Nether Essence. But, he then said, D/E the rest and you will get Dream Dust. So i D/E the 8 and got all dream dust. He said that when you D/e Things, you only get 2 of the things you plan to disenchant. I'm not sure what he meant, but if anyone knows what he meant could you explain it clearer or rephrase this theory he had? Or maybe tell me if this is true or not?