I understand, dozen may be more comfortable than twelve in speech.
I can understand using over a dozen or almost a dozen These imply rough measurement of the count, maybe ten, maybe eleven, or maybe thirteen, maybe fifteen.
But why do people choose to say/write Almost half a dozen or Nearly half a dozen when it invariably means "five"? "Four" is definitely not "nearly half a dozen", and I completely don't see the point why would anyone use this expression, but still I find it quite frequently. Does it have some historical basis or implies something beyond "five"?