To be fair, those numbers are just a snapshot in time. It's possible there was simply an oversupply of Q60s that month for whatever reason.
Hard to say if sales were already falling because previous to 2014 the G37 sales numbers included all body variants but since Q60 sales have fallen dramatically – not surprising since the new model is around the corner.
The RLX, on the other hand, is a perennial slow seller.
