Bob, my impression is as follows:

When позвонил is used, a rigid box is created.
Most of the people ( here the people mean native speakers of Russian ) find it difficult to pack many actions into such a box.

As to other perfective verbs, a flexible box which can easily become bigger
is created, so the people can pack many actions into this type of box.

In case of the imperfective verb, no box is created.

Please look into the above impression!!



Yuki