Lemurian,
Re the assertation that no airline can be found that uses the speed trend to deduce "DECEL", please see the latest FCOM 3 SOPs from Airbus that (finally after all these years) shows that they have woken up to what the operators have been telling them for years - that calling DECEL or NO DECEL based on the green light in the Autobrake switch is ridiculous.
The latest SOP states that DECEL should be called when it is felt by the crew and that it can be called also for the DECEL light and the speed trend arrow.
For years I have been advocating that what Airbus taught in their TRTOs on this issue was rubbish. They even taught pilots to call "NO DECEL" if no green light!
At least they know now how important it was all along. Another example of the "Not invented here" syndrome so beloved of many in TLS? If the "B company" did it then it couldn't be right for the "A company". Pathetic - but what a shame because they actually build very good aircraft.