On 15/08/2020 10:50, T i m wrote:
And hill climbing, more energy being used on the way up than recovered
on the way down?

How's that work then? You take a weight up against gravity, then you'll
get the same back on the way down.

Of course in practice there will be occasions when the extra 1% weight
will make you drop a gear.

And other occasions where on the way down it'll be the difference
between a tickle of throttle burning fuel very inefficiently, and
throttle shut burning none at all.

Andy