Ops -room,
I am very sure (not 100%) that this 140% is an internal SOP regulation and nothing else.
Under Ops1, Dispatch must make sure that the available DRY Runway Landing Distance(DRY at the scheduled ETA) is equal to or more than 1.67 x the QRH DRY ACTUAL Landing distance(NO REV,Auto speedbrakes,MAX MAN Braking).
Wet figures must be factored by an increased 15%.
Using full Reversers on wet runway is necessary for the reasons you may know as a pilot so I believe the company you are referring to, just wants to make sure than IN FLIGHT the flight crew calculates their landing distance (as required by EU ops) via the QRH as conditions may have changed from the time the aircraft was dispatched.(ie unscheduled rain).
(The QRH only factors 15 % for braking action GOOD(runway wet)).
The 1.67 isnt a regulation in flight anymore so the airline wants to make sure the the flight crew Landing distance Available is not 115% the landing distance Required but 140%...an extra margin as we aint all great super pilots.
Comparing your calculated and actual landing distance with specific a/b settings will not only improve your daily landing distance awareness,save unnecessary high or too low A/B settings and may also one day save your AA butt(
) in case the runway is changed at the last moment.A quick check will allow you to accept or not the given landing runway.
Hope that helps