Chart 'sort by' function help

I want to know how the Sort function in bar charts works, bacause I have a chart that displays bars according to a scale column in its table, but when I sort the table by the scale column in ascending order, it doesn’t really turns out in ascending order, maybe it is because it’s grouped by Person name, but what happens is that the bars are not in ascending order as i expected, maybe I am not using the function properly.