Asda Skelmersdale have taken delivery of new 420 opticruise 4 wheel units, & are now in a great panic over the fact that these trucks are only doing 7 to 8 mpg, scannia & Asda have said it is down to the way they are being driven,but these trucks are being driven the same as the manual ones, which get about 12 to 14 mpg, Asda have cocked up big time here. I would of thought it would be obvious that semi automatic gearboxs would use more fuel than a manual especially as they only do short runs through towns, stop & start & only 50mph on motorways.At 50mph the trucks will not go into top gear unless you put into top manually. Anyone else use Scannia opticruise & what mpg do you get ?.
they need running in maybe
or drivers need to be trained on new box
i had one yesterday it was horrid 
because i had no idea what any of the buttons did
got it sussed eventually
it has manual mode on the stalk
I drive a DAF CF with AS Tronic automated box and over the last 160,000 Kms have averaged 8.9 mpg, this is running at 44 tonnes for 50% of the time and running empty50%. However if you just leave it in auto and nail the throttle to the floor it uses a lot more revs than you need, so either use a lighter foot or try driving in semi auto and changing gear yourself. Either way its still a lot easier and more relaxed than driving a 16 speed range change and splitter manual box!
Also my truck will cruise at about 41 mph in 12th fully loaded quite hapilly if in manual but in auto it will be changing up and down at every bend or incline, if your Scanias are fitted with trip recorders that monitor speed, distance, and mpg try driving in semi auto with lower revs for a day and see how it compares!
We’re finding the same with the Scanias at our place. One hundred manuals doing 11 -14 mpg and a handful of autos doing as you say 7 -8. We’re getting another batch of Scanias in Februrary and they’ll all be back to manuals.
When we had our training on our new MAN’s we were told to manually change up before the Auto to change up when pulling hard. This seems to work wonders with the fuel. The box then reverts back to Auto after a few seconds and gets on with it.
You can achieve the same results with lighter throttle movements but its trickier!