In a new game I opened the catacombs and freed Lanilor to get up to level 1, then learned Hell Spikes. After that I could use the editor to apparently increase the skill level, but as you found the damage done and mana used actually corresponded to level 1 of Hell Spikes. I then used the save editor to increase the character level past what was needed for level 5. Just leveling up made no difference to Hell Spikes, so I unlearned it using the editor and relearned it after reloading the save. There were too many differences between the skill sections of the data.000 files before and after re-learning Hell Spikes to isolate exactly what is missed by the editor. A slightly different approach should minimize the difference, which I may be able to try in the next couple of days, or so.
