Hi Peter,
In my prior post in response to you I said that maybe the problem I have been speaking of (regarding a possible lack of precision in Creo Elements / Direct Modeling Express) amounted to just me not being careful enough in snapping to objects and parts, as you suggested. However, the problem has persisted. I think I have found a way to reproduce the problem and I have attached a file so that others can reproduce it and see for themselves what I am talking about. See my most recent post in response to FriedhelmK, above; and see the attached file I included with that post.
Regards,
Vincent