Comparison between the best-fit model from Paper VIII with the modified one from the current work. The AMR with all the clusters from SB (excluding the ones classified as [3D] main body as shown in Fig. 3) and WH clusters. The best-fitting major merger model from Paper VIII, derived using only the WH clusters, is over plotted as the solid blue line. The green solid line represents our newly modified major merger model, accounting for all the clusters from SB and WH together. This best-fit green solid curve illustrates a merger model with a 1:4 mass ratio 6 Gyr ago, followed by enhanced SFR from multiple bursts as presented in Fig. 5. The region enclosed by the black rectangle highlights the most significant difference between the old (Paper VIII) and new models.