I do not know the exact reasons, but was told by dealer it related fuel emissions and added filters etc. I was a bit miffed to.
Although in part could be to how they actually rate Power Output now, in the motorbike world some time last year pretty well all motorbikes were down graded, when I bought my Ducati 2015, it was rated at 160 BHP, but was down rated to officially be 152 BHP earlier this year or last. funny how the insurance Companies still classify it at 160 though
Insurace Companies do classify MY19 as 390 and MY18 as 407