Yes, if you are not used to it, it can be confusing, it's trying to split the cost against different pairs of dates so that you can compare options on that particular date, and for example see that if you delay your return after Saturday then CE becomes cheaper. But if, for example, you start from the bottom and then look upwards then it goes horribly wrong. Make sure you also compare single fares, in this scenario they can be cheaper, but usually that would be in LON-NCE-LON orientation rather than in your situation.