A real monoflop doesn't bouncing like a mechanical relay does.
And if the relays are switched on/off (in terms of monoflop function) the output signal is bouncing because of the mechanical contacts.
The K3 can be switched off by sending a "power off" -command via serial port. But the K3 cannot be switched on via serial port. The K3 needs a small pull down at pin 8 (ACC connector) for remote switching on. This pull down signal must not last for ever it is just a small pull down signal of several milliseconds.
For that reason I trigger a monoflop (NE555) via the relays and the monoflop turns on the K3 remotely (electrically isolated via optocoupler). For K3 power off I am using the power off command via serial port.
Mike