(Forwarded reply from our technical team):
CPU should be measured in clock cycles(instructions or bytes of instructions) at this level and time(a real world concept) is also something useful to watch.
Though percent is relative to the size of your container. What this graph indicates that the cycles(instructions or bytes of instructions) might vary well have stayed the same. The effect on time would have been measurable, but as for some one sitting down to watch web sites load there is no indecation here of a change.
Your container got bigger but there is no more or less CPU contention at 45% then there is at 25%, these graphs indicate vary little contention.