Enemy levels determine the target time for a battle, and consequently, these post-battle stats:
- Points per second
- Score
- Stars
- TP recovery
- Item and shroud drop chance
Based on the Game Mechanics guide on GameFAQs:
Target time
Given:
- Target time T
- HP at start of battle H
- Enemy level L
- Highest party member attack power Ap
- ATB level A
Thus:
T = (H * L / 16) / [(Ap * A) / (3.5 + A)] + 8
if enemy level L is less than or equal to 50, otherwise:
T = (H * 50 / 16) / [(Ap * A) / (3.5 + A)] + 8
Points per second
Given:
- Points per second P
- Target time T
Thus:
P = 10,000 / T
Score
Given:
- Score S
- Points per second P
- Target time T
- Battle duration D
Thus:
S = (T - D) * P + 10,000
Stars, TP recovery, rare drop chance, shroud drop chance
Score | Stars | TP | Rare | Shroud
================================================
> 13,000 | 5 | 8x | 5x | 1x
12,000 - 12,999 | 4 | 3x | 3x | 1x
9,000 - 11,999 | 3 | 1x | 1x | 1x
8,000 - 8,999 | 2 | 1/2x | 0 | 2x
7,000 - 7,999 | 1 | 1/4x | 0 | 4x
< 7,000 | 0 | 1/8x | 0 | 8x