Aboat six-pyramid test problem?

When testing the six pyramids, you need to first change the 64 * 64 size of the heat map into 256 * 256, and then change it into the original size, such as 720 * 1280. If so, why do you need to go through 256 * 256, and in the process of transformation, does the center need to change according to the same scaling factor?