Impression copings for Straumann tissue level implants: any issues?

Has anyone had either good or bad experiences trying to take an impression of Straumann tissue level implants using Straumann impression copings?

I just completed a case of a 46 implant (lower right first molar) with limited access. I found the Straumann plastic snap-on impression copings inaccurate.

After the first impression I attached the implant replica to the plastic components in the impression and the implant replica rotated slightly. I retook the impression with a new plastic snap on and heavy body impression material. I inserted the implant replica into the plastic implant transfer components and everything seemed solid. However the crown that was made was rotated and would not seat.

Next I used a metal closed tray impression coping. I managed to get an accurate impression and the crown seated well. However I found the metal coping not to be as stable when placed into the implant as I am accustomed to with other internal connection implants that I have used. The portion of the impression coping that fits into the implant seems shallower than those of other brands of implants I have used and didn’t seem to be as stable when I was trying to position it prior to screwing it in.

Note: I have used snap-on transfers before and some could have even been a Straumann implant without trouble. The implant in this case was well placed and the implant margin was supragingival and the snap-on fit well (rotated on the implant prior to inserting the second stabilizing component fully into the implant).

Is it just me or have others had this issue with plastic snap-on copings on Straumann implants or snap-on copings for other implant systems?