Did you that the traffic is mobile telephone user is on the six o'clock evening until nine o'clock at night. This is different from the peak hour on the user's cable telephone service (PSTN) occurred during business hours between ten o'clock until two o'clock noon.
Why? From my analysis, that the personal mobile phone use. So that at the time in the road after office hour and at home, is usually used. For telephone and cable, usually used in the office at noon.
That is, mobile operator, does not give discounts on the day's peak hour. Operator will give discounts and even free at the time of low traffic, usually from middle of the night until morning, sometimes up to twelve o'clock noon. Operator do not want the revenue loss.