@TrippZ currently Klipper applies IS to segments too small for RRF to apply IS too. The cost is more deviation from the path commanded by the GCode, which the Klipper documentation refers to as "smoothing". See https://www.klipper3d.org/Resonance_Compensation.html#after-enabling-input_shaper-i-get-too-smoothed-printed-parts-and-fine-details-are-lost.
The latest RRF 3.5 builds are able to apply IS to some shorter moves, but by no means all short moves. We already have work underway to support IS on all short moves, but this will be at the expensive of "smoothing".