I would say starting from PP in LOD, a 3/8 turn (foot position) is typically correct. However, if you continue that rotation of the body to lead into the next step, it will terminate in what looks like a 1/2 turn. The body never stops moving in the traveling dances, specially the slower Foxtrot and Waltz, when executed right. Hence, even though the turn in a VW is 3/8 turn for the 1-2-3 portion, the body continues this rotation so that it appears that a full half turn has been performed. This is to my understanding of course.
However, some people take it to the extreme and go around in circles, but that is a subject for a different discussion.. ;o)
Enjoy.
Sri.