this is an awesome guide. the only thing is that rust (and most debuffs it seems) does not take off 51% of the enemies ap off, it takes 51% of UR MA of the enemies ap off.
actuall formula from the /gg ftw wiki:
Enemy AP - (MA - 49) x Attack Reduction x 16
or, for easier calculation: Enemy AP - (MA - 49) x 16 x Attack Reduction
example: i was able to solo captain skull the last time i was on seriously (which was a year ago, but still) my strategy was to mist (if it wasnt up already) then rust. after that he did single/double digits on me, if anything. that is pretty significant since im a 1441 pure MA with 1k hp and a myshop lk set (west wind iirc). this basicly let me pound on him with rush (the only attack skill i had at the time, pretty stupidly) until he died. i have 18 boss seals from doing that, so i would say its pretty effective.
this means that u can theoretically reduce a powers AP to 0 if u have enough MA. now thats probly going to be a bit hard, but still possible, and u can neutralize most powers ur lvl or lower of similar equpiment (u both have myshop, for example) i would imagine