An illustrative hysteretic transition remembers the direction of approach. Drag the temperature back and forth: the material transforms on heating above the nominal Tc, reverts on cooling below it — and the loop between the branches is data. The 8 °C separation is an illustrative teaching value, not a material’s hysteresis width.
Schematic loop: nominal Tc = 68 °C with the heating branch switching at Tc+4 and the cooling branch at Tc−4 (sharp sigmoids, teaching parameters). The reporting rule it teaches: a hysteretic transition has a heating value, a cooling value and a width — state all three plus the ramp rate. Not data for any real material.