Thank you AgX for the change. It's true that there is an advantage to being able to focus 'at telephoto' and then zoom back to 'wide' but, to tell you the truth, sometimes I feel better re-focusing at that 'wide' length. Chalk it up to paranoia perhaps but I really wonder how accurate even Parfocals are with regard to 'holding that precise focus' at all focal lengths. I guess that is what it must really be on my part: paranoia.
Thank you for the clarification, AgX, and also to the others for the necessary addenda to my original question. There is so much to gain on this forum from many with different dimensions of knowledge out there. - David Lyga