This phone shows data usage statistics in “Quick settings panel” as sum of monthly usage and also in cycle of monthly , when you go to the long view of data usage statistics you will see a graph of usage which is of no use because the line graph points are pointing sum of data usage so you will get no information seeing the graph.
My suggestion: In the graph add data usage points as daily usage and below there / up there show the sum so that it will help users to track or get information about that.