In BG2(EE), the effect of the 'Horror' spell / ability is very different from the same effect in BG1(EE). In BG1(EE), creatures struck by this effect only try to escape from the caster. But in BG2(EE) this effect is somewhat similar of the action of the spells like 'Confusion'/'Chaos' (and like that), that is, the creature struck by this effect begins to perform one of follow actions: try to run away from caster or continue to attack a caster. With this, in approximately 7 out of 10 cases, the creature will continue to persue and attack a caster. If the caster has become invisible (by one or another way), creatures affected by this effect will randomly move around the game map.
In this regard, I propose to replace the 'Panic' effect, which is used in this spell/ability to 'Morale break' effect.
For the effect of 'Morale break' , I experimentally chose the following values: the field 'Value' I set to '1000', and the field 'Modifier Type' - 'Set (1)' (for this changes I used 'Near Infinity').
A brief test showed a good result - creatures struck by this effect try to escape from the spellcaster and will not attack him for the entire duration of the spell. And they will return to their normal behavior when this effect ends. I.e. same behavior as in BG1(EE).
I would be glad if people with good understanding of this game or game engine, will express their thoughts about this.