As long as I have followed F1, even during a race there are fluctuations. Sometimes driver A is lapping faster, sometimes Driver B. There is no reason to overanalyze one specific part where Rosberg was faster. Hamilton beat him fair and square by the chequered flag.

It reminds me some of the early season arguments that Räikkönen was "faster" than Vettel, just because in some parts of the race he seemed to have better lap-times. This despite Vettel finishing well ahead at the chequered flag. Let's not start clutching at straws.