Well coming from a well respected former alchemist on Gemini, he says that no matter what he makes (his alchemy is lvl 30, and hes been playing since beta) he always jumps +4 or 5 he came out of retirement, briefly, to make 12 ying yang suits, 15 wizzy suits and a few other 5 parter compounds. and did not fail once (he also gave them all away)but ask him to make a simple +2 or +3 compound, he can't. He will over jump everytime.That's why he retired that alchemist.

So, either he is a liar, or rank 25+ is not something to look forward to.(hard to make money when all you can make are real expensive items that only a few can afford.(and after they buy it, never need another one))