The cumulative frequency curve in pareto diagram

In the pareto diagram provided, the vertical axis on the right, scale from 0% to 100%, isn't the 100% of the cumulative frequency equal to the total frequency of the three brands? Which means, shouldn't we create the first point of the cumulative frequency curve in the same y-value of the first bar? It seems it would be easier to read or understand in this way? Or do we always use different scale between the frequency and the curve?
Thanks.