Oh my Lawd, how anal does this website have to be, this question belongs in this forum oh and this one can't go here cause it belongs in this one, are you really that anal about organizing questions? don't you have anything better to do like oh I dunno, maybe ANSWER THEM? you come in here just to say you moved the damn question and don't even attempt to answer it? if your not gonna answer the damn question then don't post in the fucking thread, I don't care if your a moderator or not, this shit is seriously pathetic.
and to the OP max codeine is dependant on your tolerance and past experience with the drug. 320 is quite a bit, it sounds like your tolerance has exceeded the need for codeine, as well there is a ceiling amount past 400 mg the effects no longer increase, The Lethal Dose for 50% of the population is 800 mg, but that being said going over 400 mg is pointless due to the ceiling affect.
Be safe
and have fun
B