Well, either the coaches are doing a shite job of grading the rowers or its deliberate, but > 16 seconds difference between the 2nd & 3rd IVs in the wrong order is noticeable to all. Its not "stupid", its logical, your faster crew (by > 5 lengths) is your higher crew, ie 2nd IV in this example.
As far as changing combinations, Shores 3rd IV was a completely different crew a couple of weeks ago. Not one of the five crew members the same, one was in the 1st IV, one in the 2nd IV, that's cool, change combinations, but they must be in the correct order of boat speed, the difference today between the 2nd & 3rd IV was huge.
I respect Shore, they are better than that.