It really is not that complex =\.
Anyway, here are some of my level ups. For the time, I wait until the "Time Saved" thing goes away, then press b twice and then a. Then immediately turn the DS back on and spam a until I'm at the title screen.
For all of these level-ups, attack method was Me-Enemy-Me.
1) Date: 8/24/09
Time: 20:42
Notes: Enemy must HIT your character
Ogma!Mercenary: Hp, Str, Skill, Spd, Luck
2) Date: 8/24/09
Time: 02:20
Notes: Enemy must MISS your character
Ogma!Mercenary and Barst!Fighter: Hp, Str, Spd, Def
3) Date: 8/24/09
Time: 22:30
Notes: Enemy must HIT your character
Ogma!Mercenary: Hp, Str, Skill, Def
I have more but these are the best I have found so far, and the others I'm not sure if you have to hit or miss the enemy. Also, I haven't tested each of these with enough characters to find the actual RNs they produce, just that for Ogma!Mercenary they all work. The second was tested with Barst too.