[Jens]

Another example:

A tries to speaks with B on the phone who isn't around and leaves a message and asks B to call back.
A tells C that he's waiting for B to call back.
Later on C wants an update on this:
1. C: Did B call you back?
2. C: Has B called you back?
3. C: Did B call you back yet?
4. C: Has B called you back yet?
I guess the implied time reference in all these sentences is "at any time up to now",
which "normally" (right, what is normal) calls for present perfect.
But what about the simple past sentences?
Would they be prefered in AE?
Where is the difference in AE?
Does any of these sentences sound unnatural?
Specifically:
Does 2. express more importance than 1.? Is 1. a more neutral way of asking?
What does 3. add to the meaning of 1.?
What does 4. add to the meaning of 2.?