Looser quality cuts (see Table 2) produce a similar result to the main sample shown in Figure 5. There is a correlation of comparable strength between age and break mass, with older clusters tending to have higher break masses. Due to the much larger sample, the statistical significance of this correlation increases from 2 × 10⁻⁵ to 10⁻¹³. Thus, the conclusion that there is a trend consistent with the sound speed evolution of a typical galaxy is not an artifact of quality cuts, but instead reflects a genuine property of the underlying cluster population.