Evergreen wasn't the first to 'consider'-Minus v1...Lufthansa,upon reading the 25-109,and the test card,after their incident b747 freighter,hong Kong 83,considered -v1 minus 3knots.This complied to the 'test card'Vef(about 1 sec prior to V1-established by the Manufacturer,as high as 3secs with the centre eng 727)for'recognition'of a failed eng'prior to V1...This all came out,along with the 'Vef'definition, with amendment 42 of the FAA 25-109,as it reads today.(Air Canada tried to use the V1-minus 5'in 1980,but dropped the idea)
JAA we're to understand uses the same criteria,but named diferently'Stop' etc.The A320 complies with the FAA25,and is very exact in the 'low weight'Takeoff case ,in that the V1 must avoid the VMCG area.
To answer the question:V1 is a commit speed after the 'first' stopping action(whether it be brakes,or 'thrust levers'-Boe/Mdc), if a failure is ' 'recognized' 1 sec',or about 4knots before V1
