I am going to second or third or fourth what was already said. To me, knockout and flameout are the same. Once you turn off the flame to the boil kettle, those "knockout" or "flameout" hops go in and you start your cooling down. I leave them in the kettle until the wort gets transferred to the fermenter. I am by no means a pro, but from the reading and research I have done, this is what it means. Whirlpool hop addition simply means, to me, drop the temp to whatever the whirlpool addition says and let the hops steep and stir for however long the time is. So, those hops sit a bit longer as they are there for the "whirlpool" and the cooling down period. With that said, there are probably other interpretations of the phrase, but that is what I have taken it to mean. Rock on!!!!!!