Yea, the rules are just guidelines, noone should ever follows it like your life is depended on it. If you waited too long to call or dont call at all, shes gonna forget the good memories about you. Having said that, dont talk on the phone for hours and hours about nothing, just call to say hi, chat for 5 or 10 min and wish her good night. This way she'll still have you on her mind and dont get bored of you, you should watch your tone of voice on the phone too, you want that deep seductive voice since she can only hear you so make that count.