The difference between the one-sized printed tights and the Extra Large Printed tights is the Fundoshi-machi design.
The Extra Large tights feature an added middle panel (Fundoshi-machi), which provides extra comfort and a better fit, especially for more flexibility and ease of movement.
Size matters!
The extra panel in the XL tights makes all the difference, not just in the fit of the tights but also in the feel of them. I am 5'5" and weigh 150lbs, waist 37" and hips 41". The One Size tights fit me, but they feel a bit scratchy, are tight at the waist and bind a bit around the upper thighs. The XL feels silky and comfy, with no bunching, binding, or rolling.
The tights are light in texture and suitable for at least 3 season wear.