I think I figured this out after I began creating this post. I did try to figure it out prior to now.

I was confused by "Err" in the current round trip but not in any of the hops. Now I realize that the error is probably occuring in a hop that is invisible; that is, no (other) information is available. I would include an image of what I am encountering but I don't see a way to upload an image; I assume I need to upload elsewhere and link to it. I can do that if necessary but you probably understand what I mean.

I am using the free version of Ping Plotter. It looks very useful and I appreciate getting it for free. I get the impression that it has not been improved for a while and generally it does not need improvement. If however I now understand what I did not understand (as described above) then an improvement would be to show "Err" for the current time for a hop even if no other information is available for the hop.