If people have been playing a long time, and many have, certain clans are clued up and will do what they have been doing a long time, that is exploit any loop holes that exist , but are given the green light to continue using, or find the new loop holes in updates of the game and use them till if, and when they are closed.
I find it hard to imagine that this is the only place they, the owners,find out about them.
As to the chance element with forging, I wondered much the same.
You are right using simple mathematics, but using simple is far too easy in the game.There are always alternative facts.
Somewhere in the game,or on the forum, or the internet is some convoluted explanation as to why lower quality materials distort the chance of the higher quality item being given.
I suspect its something to do with not making it easy to get the best equipment, as if it wasn't difficult enough already!
You may have already realised this,but if you have enough materials, you can play about with the allocations and see how the %chance changes by swapping things and notice and think, maybe I shouldn't have converted everything upwards, because now my that my four epic have been converted to legendary, my chance of getting a good piece has gone down, because I have only a simple piece as second string, where before I had two epics to use.
I have been thinking about posting a question on this subject.