<and another note, since it sounds like you're coming thru this again with another job, ive noticed that with different jobs/weapon proficiency you get different check msgs>
This is dependent on your weapon skill, not your job class. If you leveled a WHM to 30 with a maxed club skill then started up a BLM using clubs your club skill will always be maxed and the check will probably always tell you "Low evasion and defense". Switch to a dagger and the same mob will change to "High evasion and defense".
Also, the check messages and exp differ because of the level of the monster. You'll obviously get more exp for a lvl 20 IT than a lvl 19 IT. Experience is determined by what it checks to the HIGHEST level. If you had gotten rid of the lvl 16, your exp would have jumped a good deal. This is why melee should always be the highest in groups, not mages. If the casters are the highest, the group will end up with either crappy exp from low level pulls or crappy exp from melee needing to pull things higher than what they can handle.