hello to there

i am using of a2billing 1.4.4.1 and i have a problem with day and night time calculate.my provider discounted rates in night about 50%.and i want to do it too.but in start time and end time rates , just i can use for one day and it is not for a week. in normal way i must make rates for any day.means for saturday i must make a rate for day and other rate for night.i have 350 prefix and this is not normal making 350*2*7=4900 rates.
please tell me how i can design day/night plane?


thanks