In case of natural ventilation system, I agree that the upper and lower limits of the comfort band need not to change hourly because one is expecting the weather and will be adapting accordingly. But perhaps the limits should change monthly. I think this is important for two reasons:

1) to allow the blue and red bands on the temperature profile graphs to represent the true comfort band limits;
2) to properly set the windows on/off in case using natural ventilation and/or mixed-mode ventilation systems. This is important because a window in a mixed-mode will be assumed opened if the outdoor temperature is closer to the comfort band than the internal temperature. Hence, the importance of accurately defining the comfort band to make sure the natural energies are used to its full.