Left: separation of the black holes as a function of time since t_ini (since the particle splitting procedure). The blue line corresponds to the original run in Khan et al. (2016), while the orange line corresponds to our run. The light version of the blue line refers to the continuation of the original simulation data. The three dashed-dotted lines starting at 33.35 Myr correspond to analytical estimates of the merger time in the PN-dominated regime using constant values of hardening rate. The vertical line marks the initial time of our run, t₀. The horizontal dashed line marks the separation of 100R_sch, where the R_sch is the Schwarzschild radius of the combined mass of both black holes. Middle: inverse of the binary semi-major axis used as a measure of hardening rate. Plot elements are the same as on the left plot. Right: eccentricity evolution of the SMBH binary. Plot elements are the same as on the left plot.