Hopefully I can help...
The data that is being sent from the Mercedes website to the web app looks like this:
"liquidconsumptionreset": {
"value": 6.6,
"ts": 1475125942,
"status": 0
},
"liquidconsumptionstart": {
"value": 1.6,
"ts": 1475239280,
"status": 0
},
The TS is a TimeStamp - and the value is litres per 100 km.
Their code running in the browser to convert to mpg, looks something like this:
MILES_TO_KILOMETER:1.609344
KILOMETER_TO_MILES:.621371192
LITER_PER_100KM_TO_MILES_PER_GALLON_UK:282.4809363
LITER_PER_100KM_TO_MILES_PER_GALLON_US:235.2145833
MPG_Value = 282.48 / value
so for me... 1.6 litres/100km = 176.55 (the value it shows in the app is 176.6)
Then there is this curious piece of code:
b.constant("USER_CONSUMPTION_COMBUSTION",
{L_100KM:{// [l/100km] id:1,value:"UNIT_METRIC_CONSUMPTION_COMBUSTION_LONG",upperLimit:20},
MPG_UK:{// [mpg] (UK) id:2,value:"UNIT_IMPERIAL_CONSUMPTION_COMBUSTION_UK",
upperLimit:80},
MPG_US:{// [mpg] (US) id:3,value:"UNIT_IMPERIAL_CONSUMPTION_COMBUSTION_US",upperLimit:80},
KM_L:{// [km/l] id:4,value:"UNIT_METRIC_CONSUMPTION_COMBUSTION_PER_LITER",upperLimit:40}}),
The important bit being: "upperLimit:80"
So... I would expect if they changed it from upperLimit:80 to upperLimit:999 then all would be well with the world
It seems an 'easy' fix - however I don't know what the knock on impact of changing this value is without full access to their code. But it seems pretty black and white.
Hope this helps
I haven't passed this onto Mercedes - so feel free to send it across on my behalf, and PM me if they want me to send more details of how to fix their system