In order to better understand the impact of frequency noise on DARM, we changed SSFS strategy during a lock on OMC1_B1s2_DC: a 2nd order boost  was used instead of the usual 3rd order, and also we got some data without any boost. While SSFS error signal was changing as expected, no change at all was observed in B4_Q (MICH). MICH was very high and it was the main source of noise in DARM: in this conditions it is impossible to say something about the direct coupling of frequency noise in DARM. It could be interesting to repeat the test when MICH is normal or low.