CrazyGunner

I've been using Custom NPCs on 1.7.10 and I don't know if this sort of problem exist in other versions or not... I created NPC and made it use range attack with the setup like the pic that I attached to this topic. The problem is when it's using range attack, it shoot the target while stand still all the time. It doesn't make any move until the target get away too far from its aggro range. I tried changing 'MustSeeTarget' option to yes but it get even worse. The NPC try to chase the target but it walk very very slowly and didn't shot even the target stand in its attack range. It will shoot the target only when it get very very close to the target even I set its aggro range and attack range to 64. I also tried changing its tactical variants but no one of them work fine. The only thing I want is just to make the NPC chase the target while shooting... Any solution here?