Why are there 2 incinerates, and what's the difference?

I noticed as I decided to change Incinerate, that there was also a spell called Incinerate (arrow) So which do I use? I saw that the arrow has a mana cost and cast range. So do I modify both to my standards, and only give the hero normal incinerate? Or do I need to use both? Any help is apprieciated (I'm starting to hate the hero this spell goes to... It's been cuasing me ALOT of problems and stress...)

All incinerate based abilities use the data for the non-arrow incinerate, I believe, or it could be just all the arrow incinerates.

Buggy ability.

One incinerate is a passive ability, the other is autocast, which is bugged and uses the stats of the passive ability instead of it's own (still waiting for blizz to fix this) so you can't make multiple custom versions of it, you can only make one by altering the default incinerate ability.