Right but you will not buy a camber arm if your toe is out of whack, you'll want the toe arm. There will be some toe change when you lower on springs, but it will not be to where you need a toe arm, coils on the other hand will allow you go to as low as you want.
The camber arms will correct the camber up to 1 degree, which is usually the amount of negative camber you get with a 1" drop give or take.
So I guess the camber are arm does change the toe, but like I said, you don't buy it to change your toe, it's mainly for your camber.
The 3 arm kit on the other hand will allow for 3 degrees of change along with some toe movement.
No need to over think this. If you are going to drop on springs or only drop to 1.5" on coils, you only need 1 arm .. any more and you will want the 3 arm. Don't worry about toe really if your alignment doesn't show anything wrong with it.
You said the guy at the shop says caster and toe change when you mess with the camber, but you have to remember, when you lower, you are going to get more negative camber, the 1 arm camber kit is the same thing you have on there OEM, but this one is adjustable. It pulls the wheel back to near OEM specs.
