(PlayerLevel-MonsterLevel)*4 is the level correction factor, it's simply included in the formula you used.
to clarify:
Level Correction is a penalty you take for fighting monsters above your level, approximately 4 evasion for every 1 level of difference(either way). In the case of Greater Colibri, they have a base evasion of 339, but they are 7 levels higher than you, so they gain the equivalent of 28 evasion to total 367 level corrected evasion. This means that you need 367 accuracy to attain a 75% Hit Rate on the monster. In order to find your actual hit rate, you take your accuracy, subtract the monster's level corrected evasion from it, divide it by 2, and then add it to the 75%.