FE_Builder_GBA -- If you have any questions, attach report7z

Anyway, if you really want to stick to FE6, here’s your solution for the cap level:
Open the hexeditor of FEBuilder.
Jump to 0x25132.
The value should be 0x14. Be careful, it’s hexcode, so 0x14 = 20. If you want a cap level at 25, change 14 by 19.
Then jump to 0x17754.
Repeat the operation.