Update : Another cold morning (-21°C). Plugged the EBH for ~3:30 hours. c°WT showed 15°C. Had to use a little bit of heat. I did 6.4 LHK AVG...
On the returning trip, it was way better. I quit only ~2 hours after arriving, so c°WT showed 31°C when starting! This gave me the opportunity to do 10.9 LHK in town and 5.0 LHK after the highway, last part increased it from 5.0 LHK to 5.2 LHK. Don't know what I did better in town, but only +0.2 LHK is good in comparison to the +0.4 LHK I see habitually. So I really kicked ass! I think this can be explain by the fact that there was no traffic and I could P&G better.
Hit 682 km today, gas gauge is a little bit under the 1/4 mark. AVG of distance travelled in my 2 last tanks was 685 km! So I did lot better (thanks SG-II)
.