JazzyKex, I am not going to engage with your lengthy dissection save for two things:
1. to say that you misunderstood my sentence that led you to believe that rotation was before V1. My poor English grammar I guess. Sorry about that.
2. to say that our exact progress down the runway as measured by me was by looking out the side window at known reference points, and the picture at the front is imagined.
You have the type, its the trusty 738. I've given you an airfield elevation - sea level more or less as makes very little difference. You don't need a name. There are no airfield related restrictions to be factored in.
If time and time again I feel brakes graunching (protesting) at the end of a landing roll on 25 at Stansted which has included use of reverse thrust on touch down, and that's apparently necessary in order to make the last fast turn off, then I can start making some assumptions can't I? I go to Google Earth and find the approximate median of the all the rubber marks at touchdown, and measure the distance between the rubber and the SR Technics fast turn off, I can hazard a guess that stopping one of these things from flying speeds with no wind to speak of uses up most of 3000 feet more often than not. Sometimes of course, it can't be done with any comfort remaining so we sail past to the end exit point.
So I am not one to unconditionally accept that if I possess Perf A calcs in my sweaty hand or programmed into my machine, QED I can leave 2300 feet behind me when I start to roll. If I notice that my wheels leave the ground with only 1800 feet of runway remaining, I might perhaps wonder if those Perf A calcs I relied upon were yer actual gospel. They might have been ... just ... if it is further a fact that another 1200 feet used post V1 to wheels off is typical. I don't know. Sounds feasible, if a bit tight.
Maybe the Performance figures do easily show that just before V1 I can indeed stop well inside my imagined/roughly estimated 3000. I don't doubt the theoretical feasibility of that either.
But my question wasn't "is it ok/legal?". I suppose the gist of my question was, to borrow a word from 11Fan's first take on the thread, "Is it prudent?"
Why did the crew of one flight out of very many similar flights decide to do something different which relied on reduced margin for errors/failures/safety with corresponding gain that could only be measured in time/economy?