I did same measurement with REFL51, REFL135, POP17, POP45, AS17. The calculated asymmetry was 3.36(1) m.
Actually, I had one mistake in privious post.

L_d = -theta_d/(2 omega_m) c,

is correct with my difinition.

Measurement detail

1. Lock the arm cavity as usual with REFL45
2. Find optimal demod phase by using the script used in privious measurement.
3. Calculate L_d by obtained theta_d

The jupyter notebook and the measured data was uploaded here.