How do I use anglelerp?

I trying to make a Boss shoot missiles at the players current position.

Currently I do it this way:

anglelerp(Boss2.Angle,Angle(Boss2.X,Boss2.Y,Player.X,Player.Y), 60*dt)

But the thing that confuses me is, that when the Player isn't moving, the bullets aren't coming as a continuous stream, instead they have some kind of random angle offset, and look more like a spray.

What is causing this?

Edit:

Ok, after 3 days of working on this issue I just used "set angle towards position" and I fixed it.

I'm kinda mad at myself that I didn't think of this earlier... but, uh, at least I fixed this.

Still it would be awesome if someone would explain anglelerp to me and lerp and how/when to use them!