Multishot is the next evolution of the protocol between the flight controller and the ESC. Just like OneShot was better than PWM, Multishot is better than OneShot. Much more resolution. Much more precise control. That's the promise. But first you have to figure out how to install the right firmware and get the options configured.
MULTISHOT IS EXPERIMENTAL FIRMWARE. RUN IT AT YOUR OWN RISK. Especially on F330 ESC's, there is some risk of burning them.