What Happens When You Scale Down P and D Proportionaly?

If you take your current tuned Proportional (P) and Derivative (D) values and drop the entire scale substantially (for example, cutting both in half while keeping their exact mathematical ratio intact), you fundamentally change the authority of the control loop.

Loss of Connection and Authority: By dropping the P-gain substantially, you strip away the flight controller's muscle. The helicopter will feel loose, mushy, and disconnected—almost as if it is floating or lagging behind your stick inputs because the servos aren't being pushed hard enough to fight external aerodynamic forces.
Under-Damped Damping: Because D-term scales down alongside P, the system loses its shock-absorbing resistance. While you won't get high-frequency servo buzz, quick direction changes will feel sloppy and unstructured, lacking that crisp, mechanical snap.

While maintaining the P-to-D ratio keeps the relative damping balance correct (preventing violent over-oscillation or severe under-damping relative to each other), it completely ruins the gain bandwidth required for a locked-in flight feel. Modern FBL systems rely on a certain threshold of proportional stiffness to anchor the disc in space.

Dropping the P/D scale substantially will move you completely away from that locked-in, iKON-like precision you are chasing, resulting in a floppy, unresponsive helicopter that requires massive pilot compensation to fly cleanly.