If i recall, a couple of years back an Emirates crew ex Melbourne failed to notice the unreasonable A340 weights, hence t/o performance data as they also routinely flew the A330. Came as close to disaster as the slatless BA 747 rotation out of Jo'berg last year.
http://www.pprune.org/rumours-news/3...strike-ml.html
http://www.atsb.gov.au/media/1358013...012_prelim.pdf
i had a friend at United swapping almost daily between the 757 & 767. apparently he wrote the type on the TOD card, and i've heard it's part of the SOP taxi brief in some operators.
i believe there's a common type rating for the 777 and the 787.
the FBW logic can model performance anyway the manufacturer (or customer) desires, but physics is still physics..