Effective teachers know that using feedback from assessments is the key to achieving mastery.  Thus,  we can't be scared to reteach.  This may mean our classes across the day don't pace together or even get identical lessons.  Shouldn't that actually be the norm?  If learning is messy and the goal is to achieve mastery, you would certainly expect less standardization.  It has to be about the individual, as well as individual classes.