Chica_d, did you know that in every normal healthy female cycle there are only a few hours that the egg can get fertilized? This is the 24 hours after ovulation.
Your period is at the opposite end of ovulation in this cycle, 14 days away.
The pill manipulates your hormones to follow a fixed 21/7 day cycle and it stops ovulation from taking place. By the time the inactive pills roll around, it is too late for the body to ripen an egg and release it. The body has been forced into submission and to give up trying to ovulate for that cycle. The correct hormone mix for it to happen is just not there in your body.
The 'period' you experience during the 7 days are also not menstruation. The pill stopped the uterus lining from preparing for implantation so there is nothing to shed during menstruation. It is caused by withdrawing the hormones and allowing the uterus to bleed. For this reason it was found safe to use the 4 bleeds per year pills and the once a year pill is currently in the approval phase.
Depending on the pill you take, the same hour every day is more or less important. The lower the dosage of hormones, the more likely it is that the body's own hormones will take over when you do not take it on time. Most pills has a 24 hour grace period. This is not good for your hormone levels and will likely cause strange bleeding patterns so it is recommended for your own sanity to take it every day at the same time.