In order to easily modify the character's level-up data I created an Excel workbook which only needs the raw hex data and it calculates all the net values so that one can easily tweak or create curves for the various character statistics. I also included charts so one can quickly evaluate changes.
The workbook contains 13 spreadsheets, one for each playable character.
I created the workbook in Excel 2003 SP3, so you don't need the latest version to open the file and use it. You do however need the Data Analysis Toolpak as an ad-in to Excel. It includes base conversion functions that are required to make the calculations work. It should be included in Excel it just may not be activated just because it isn't by default. All you need to do is to go to the main menu in Excel, open Tools > Ad-Ins and then check the box next to "Data Analysis Toolpak".
Hopefully someone will find this useful, it certainly helped me revise the level up data for my hack quickly.
http://www.finalfantasyiv.net/host-files/hacks/character-level-helper.rar
We have EVEN MORE themes now, but some old ones are gone...