Whilst i agree the price of oil being down is an undisputed positive for the company the fact remains that there is a shift towards fuel efficient cars and even electric cars. This is a long term structural headwind that will play out in due course which is why management are attempting to diversify the businesses earnings.
However whilst the market may expect this trend to be linear my thoughts are that any shift downwards in demand for oil as a result of a shift towards renewables towards will result in lower equilibrium price of oil which will in turn cause a decrease in the demand for electric cars.
As such the market may be extrapolating the recent 5% decline in volumes into the future without any consideration for the dynamics of the market