You will never, ever see a real time weight for any flight.
The primary reason for that will be that if you sign off on any loadsheet which says you are departing at your RTOW you are probably at least ten tons over that weight in truth.
Reason:
-unrealistic average weights for passengers
-hilariously unrealistic weights for carry on bags. I did a flight to Toronto a little while back and the queue of pax lined up in the jetway bent almost double under the weight of their carry-ons looked like a 19th century expedition to discover the source of the Nile. If I had stood in front of them with cheroot and a pith helmet we could have had a tableau vivant.