Distance is the distance where we target it, test the spell and cast it in a short range and long range
You can "feel" the difference and where it stops
For your spell, you doesn't use Speed = Distance / Formula, that's why anywhere you target, the distance will be the same whereas my spell formula, your unit will get to the targeted location, EXACTLY, it doesn't offset pre-setly just like your spell, always goes to 1000 range, but the player targets in a short range like 400 or 600 perhaps