I think the answer is that in order to find the mode of a set of data you work with it before you sort it into bins.

Let's say you have permissible data values y_{j}.

You take samples and observe n_{j}occurrences of each y_{j}

The mode of this data set is the y_{k}such that n_{k}is the maximum of all the n_{j}'s

Mode (statistics) - Wikipedia, the free encyclopedia