Duration of temporary transformation phases, defined as a period of time between two transformations with opposite derivative signs: namely, one transformation to lower K₀ followed by a transformation to higher K₀, or vice versa. We label cool-core phases (CCPs) as those whose temporary core entropy value is lower, and non-cool-core phases (NCCPs) as those with a higher temporary entropy. The CCPs are shown in blue, and NCCPs in orange. The short vertical lines at the top of the histogram mark the mean and standard deviation of the distributions. For comparison, the solid (dotted) line histograms show a different and more inclusive (restrictive) selection criteria for transformations. Overall, CCPs are typically shorter than NCCPs, and the distribution of durations for the NCCPs is suggestively bimodal.