Hi Mark, the motor assistance should be continuous while you are pedalling continuously.
I tried using the pedelec sensor on one of the original Magic Pies
(which was not programmable) and I found the pedelec function to be far too strong.
Even though the level of assistance does vary in relation to the pedal speed, it was too powerful for my sort or use as it felt like an "all or nothing" type of output.
Mine became a bit temperamental at times, so I eventually removed it from my bike completely as the throttle makes it a lot easier to control the exact amount of motor power you require.
Alan