I got in five Impulse titles and so far have listened to "A Love Supreme," which may well be the same mastering as the earlier SHM-CD, doesn't sound exceptional so I would guess it is not the same mastering as was used for the SHM-SACD. I have neither so can't compare.
Listening to Ballads now, which also sounds as if it could be from a 2011 remastering or so.