Hi,
On my ecu(emerald K3) the soft cut uses ignition retard and fuel pulse cuts to let you know the(user) pre set limit is reached, you can drive through it if need be, but when the hard cut limit you set is reached it cuts all sparks and all fuel pulses, till below that rpm set.
I also have a buzzer instead of the shift light ran from the ecu at 6400.
tabetha