I know this thread is very outdated but hopefully some of the hivemind that started it are still around.
Are these formulas still accurate? I see alot of this discussion was using items from Helms Deep and item levels in the mid hundreds but currently items levels are now 400-422 and still growing. Is the math still capable of these changes or have the systems changed so much and the drive of understanding not kept up?

If the math still works out, can it be used to predict gear pieces? Could i set up a way to put in the stats of an item level 406 and theorize what it would be at 414? Or 450? Of that same quality? Could the same be said for essences and knowing that they are now versus what they could be later?