Power spectrum density and cumulative sum of the PSD of phase residuals (Φ_n) for target HR 7672. The back curves represent the close-loop values. The red curves represent the pseudo-open-loop values, signifying the scenario without a fringe tracker (H_ϕ · L). The six lower plots show the reverse cumulative sum of the power spectrum. Over 100 s of a single scientific DIT, the residual standard deviation is 71 nm (UT3-UT4), 86 nm (AT2-AT4), 86 nm (AT1-AT4), 93 nm (AT2-AT3), 93 nm (AT1-AT3), and 80 nm (AT1-AT2).