Maybe obvious and I don't have a lot of detail; and, others have already shown (maybe indirectly) that the blends of the ISI impact the IMC.  But here is a coherence plot showing huge coherence between the ISI inertial X motion and IMC-F between 50 and 130mHz.  The blends here are the Quite_90s, I'll look to get some comparison when we run the 45mHz blends.