Let's use Rydia as an example again:
Lv70 --> Lv71: 1 2 3 4 5 6 7 8
---------------------------------------------
|Strength.......36-->35|35|35|36|36|37|38|36|
|Agility........33-->33|32|33|34|34|33|36|33| Each column shows a
|Stamina........34-->34|34|33|35|35|36|34|34| different possibility.
|Intelligence...63-->62|63|63|64|64|65|66|66|
|Spirit.........54-->53|53|53|55|55|56|57|57|
---------------------------------------------
Hence! From the level-up to 71, until the final level-up to 99, changes to
statistics are picked from a list of eight (8) character-specific sets.
Rydia's possibilities are the following:
-----------------------
| \Str|Agi|Sta|Int|Spi|
|1/ -1| 0| 0| -1| -1|
|2\ -1| -1| 0| 0| -1|
|3/ -1| 0| -1| 0| -1|
|4\ +1| +1| +1| +1| +1|
|5/ +1| +1| +1| +1| +1| ----------------
|6\ +2| 0| +2| +2| +2|<---/ These two are /
|7/ +3| +3| 0| +3| +3|<---\ the best. \
|8\ 0| 0| 0| +3| +3| ----------------
-----------------------
Petit copié collé de cette page : http://www.gamefaqs.com/psp/615911-final-fantasy-iv-the-complete-collection/faqs/49382 donc y'a bien un moyen d'optimiser ses stats 