The JAR accelerate-stop definition differs from the FAR definition in that the JAR includes the stopway in the calculation, whereas the FAR determines that the aircraft will stop on the runway itself.
Eh, no it doesnt!!!!! The FAR's permit you to use Stopway and Clearway, but they omit a line-up distance, so they almost guarantee that you will NOT stop on the runway itself!
If V1 is called early (beware the lawyers if is is found to be a factor in an accident!) then it is not guaranteed that the a/c will achieve lift-off before the end of the runway, following a power-plant failure nor achieve the 35' screen height (15' if wet or contminated conditions).
Dont get fixated on a single V1 speed, "generally" there is a V1min and V1max, for most modern aircraft its possible to provide the crews with all 3 V1 values, the crew can therefore decide which V1 speed is suitable for his/her aircraft on a specific runway!!
Mutt