One thing I was taught when learning to call ducks was to call at wings & tailfeathers. I think if you can keep this in mind while hunting, it will make you more effective in your calling and should offer more opportunities to kill more birds.
With that said, I don't ever call at birds that are coming right at me. There's no point. If they are coming at you, more than likely they have already seen your spread and are coming for a closer look. You don't want to do or say(calling) anything unrealistic. I don't think you would need the high ball really either, unless you were calling birds a couple hundred yards off and just trying to get their attention.
In my opinion if you stick to your basic 5-7 note hen, with a little feed chuckle here and there to seal the deal you will be more sufficient in your calling and the kill ratio should rise.
Fowl Language Duck Calls:
The Call Ducks Swear By.
Git R' Done