I do it constantly, going from Eco and up to S and back again. It harms nothing. It is no way to maximize range on battery, but most of us are not interested in maxing the range.
It is not going to harm your bike to use its electric drive option vigorously. It is designed to take it.
For relatively-max range, turn
off Torque sensor and use plain ol' Cadence-only, and...pedal more, of course!
Cadence-only sensor is what I generally use. I adjust the assist level to my current desire, depending on how hard I wish to pedal. Am limited by knee injury, anyway.
Cadence-only sensor uses less current, for instance; it maxes out at 15A in S, as compared against 20A when you add in the Torque sensor.
Cadence-only sensor is less draining of the battery in all other settings, too. For instance, in ECO it limits the current to no more than 5A. In Level 1 the current is limited to about 7A
* (I think) and Level 2, 10A (something like that) and Level 3, 12A and in S, it allows up to 15A.
And if you merely are turning the pedals, or a slightly-dragging freewheel turns the pedals while you air your soles in the breeze, you will draw the allowed-current from your
xx-amp hour battery IF the load applied asks for/demands that much current.
BUT if you have the bike in ECO, you may be going 20mph on the level and definitely pedaling to get that 20-per, yet only drawing down the battery at a gentle, life-sparing 5A rate.
Lower current draw is said to extend lipo life.
The two sensors add, the Torque atop the Cadence. Turn on Torque sensing and you
up the maximum possible
Sport current, from 15A to 20A.
Cadence sensing is always "there," and Torque sensing, when enabled, stacks on top of Cadence sensing, so to speak, if I am not mistaken (I stand and request to be corrected).
*am too lazy today to go and run the bike at the various levels to verify the current allowed by Cadence sensor-only mode. But you can! that "7" may be "8". At any rate, Cadence sensor is dumb in its way but smart for maxing battery range, as you tend to use less current.
BTW: it is not "miles per Volt" that makes most sense in relating economy to others, but Watt-hours per mile, just like the display in its secondary mode (push ON and + together) directly informs, because Watt-hours is the same unit of measurement as the battery capacity is rated by. For instance, if your battery can provide 500 Watt-hours in actual practice, and you are drawing only 10 Watt-hours per mile, you KNOW with a certainty that your battery will last for 50 miles.
My own bike's battery, in a deliberate full drain test some time ago, provided just about but not quite, 500
useful Wh. Past that, it was easier to just shut it off and pedal. That 500WH real life figure will continue to decline with time and use as my bike's battery ages.