Do you have the correct wheels chosen in the menu? (I guess yo have, but just to make sure….)
I have the 20” Überturbines chosen and it seems to predict very good on the 20” Überturbines. In winter I have 19” studded tyres, but its the same 235 width, and the same diameter. I do not see a clear difference in consumtion between the tyres so I use the 20” setting for winter as well. I took two screenshots on ”trips” today, as ther was a facebook thread discussion about that function.
First pic, started the nav to the work, in the middle of the run there was traffic that held my speed down sa little, otherwise more or less spot on.
The second pic, on the way home a bit more traffic* but quite ok flow.
View attachment 772611
View attachment 772612
*) A bit more traffic = with our norms up here. Not-hillbillies would say ”didnt see a single car”