once you get in the range of ranks between 50 and 10 things will change a lot. defenses of even 50% and more are possible when you are at rank 500 with a good defense. but when you are in the topspots things will change a lot and your def will go down extremly fast.
i usually start with ridiculously high defense stats in the first 2 days because also lowranks can attack me. from midweek on it will get worse, when get too far ahead of the lowranks...on saturday i barely see a hold at all sometimes....