So to break it down, Casting Time is a field found on each Ability in the Object Editor. It acts like a delay before the unit even attempts to "Begin casting" an ability. This is not what we're concerned with, I just think it's important to know the terminology so we can ask better questions and understand how the game works internally.
What you're concerned with is the
Art - Animation - Cast Point, which is customized on an individual Unit basis:
View attachment 492572
As seen in the picture, the Archmage has a
Cast Point of
0.3 seconds.
This means that it takes
0.3 seconds for the Archmage to execute any of his abilities. So if you pressed the Summon Water Elemental hotkey you would get a Water Elemental after 0.3 seconds as long as this sequence is not interrupted. This is why you're even able to interrupt your casts in the first place.
Alternatively, the
Cast Backswing field is how long the Archmage will continue to "cast the spell" after it's effects have executed. In other words, after the Water Elemental is summoned the Archmage will stand there, essentially disabled, for another
2.4 seconds. Note that you can issue a new order to interrupt this entire backswing sequence. This backswing really only exists to make animations smoother, especially for CPUs, since the animations would otherwise cancel abruptly. This is where the concept of animation cancelling comes into play, if you've ever heard of it. If you haven't, you've undoubtedly been doing it all of this time.
The issue with this Cast Point mechanic is that it applies to ALL of the abilities your unit casts. Meaning if you reduce the Cast Point to 0.00 seconds it will make ALL of your abilities "instant". You have two
solutions to this problem:
1) Use an ability like Berserk as the base for Dash. This ability is "Instant", meaning it bypasses the entire Cast Point/Cast Backswing system. You should be able to use the Flare ability for the Point targeted version since it's Instant as well.
2) Use a system like
this (shameless plug) to control the Cast Point for everything. But this may have some unwanted side effects, it's not very battle tested.
