Redshifts when the linear density contrast for the mode k = 2/100 kpc⁻¹ with T/T_c = 2 × 10⁻⁶ reaches unity for various masses and interaction strengths. Both the superfluid case (solid lines) and the corresponding non-superfluid case (striped lines) are shown, illustrating that the same features can be found for a choice of parameters that satisfy the constraint from cluster collisions on DM mass and self-interaction.