Thanks for weighing, all. :)
It appears to be just the way it is, in terms of how they chose to chop off the samples.
The available voices is 512, and I have 32 GB of memory in the computer, so there is close to 28 GB of memory available to Play.
The Play documentation talks about setting/changing a parameter under the Streaming tab in the settings, for the Audio Engine - with a range of 1-5 and a default setting of 2. I see this NOWHERE outside of the documentation - I can't find that parameter anywhere in the user interface, so it appears to me to be some documentation artifact, and not something that exists anymore.
I have read nearly 50 pages of documentation in the past couple of hours, trying to educate myself on the Play application, and have to explore the available articulations and my ability to use those to control playback, and hopefully I'll work through how to employ a sustained sound beyond the sample cutoff point, where the additional triggered extension note doesn't really have an attack, so that it blends into a bow direction change for additional sustain.
Bob Bone