I suggest an Updates entry, saying I-20 was relocated (or "slightly relocated") between waypoints 358 and 361, to alert users that there was a change that they might want reflected in their list files, even if there is no change to the route file. People who want to view the change as declinching (not me) can use those points to indicate the part of the route they've no longer clinched. If the old and new alignments split within the footprints of the existing interchanges, that's close enough, never mind 1PPI. No need to add new points, or relabel existing points (the Updates entry will take care of that).
When I-80 in California was rerouted to the new eastern span of the San Francisco-Oakland Bay Bridge, I inserted new points at each end of the old alignment/new alignment split. The western split is so close to an existing interchange that I had to mark the resulting NMP as a false positive. Since that point is in use, I'd leave that alone, even though I didn't consider the bridge replacement as a de-clinch. Later, I traveled the new bridge, planning my trip to do that in the toll-free direction.
