@rex_sl From the release notes, the M593 L factor is described as:
... the minimum fraction of the original acceleration or feed rate to which the acceleration or feed rate may be reduced in order to apply input shaping. The default is 0.25 and the acceptable range is 0.01 to 1.0.
ie if the commanded feedrate is F1000, L0.25 would allow the feedrate to reduce to F250, while L0.75 would only allow it to reduce to F750. So the least amount of reduction of acceleration or feed rate is from the highest L value.
I have updated the M593 Gcode dictionary entry to show this has changed in RRF 3.5.0-rc.2.
Ian