W204 C class mpg display

[loggo]

Just a small thing but does anyone have any idea how this is calculated by the car ?

On a run mine will settle down to 51.4. Not 51.7, not 51.1 just 51.4.
After 20 more miles it will jump to 52.3. Not 52.8, never 52.2 just 52 .3.
I kind of expected an ongoing progression but all I get is the same figure with a 0.9 jump.

Any thoughts please ?

[romeogolf]

loggo said:

Just a small thing but does anyone have any idea how this is calculated by the car ?

On a run mine will settle down to 51.4. Not 51.7, not 51.1 just 51.4.
After 20 more miles it will jump to 52.3. Not 52.8, never 52.2 just 52 .3.
I kind of expected an ongoing progression but all I get is the same figure with a 0.9 jump.

Any thoughts please ?

It converts from metric so the "background" figure is measured in litres per 100km and then rounded to 1 decimal place.

5.5l/100km = 51.4 mpg
5.4l/100km = 52.3 mpg
5.3l/100km = 53.3 mpg
5.2l/100km = 54.3 mpg
5.1l/100km = 55.4 mpg
5.0l/100km = 56.5 mpg

[loggo]

Embarrassed to say that I would never have worked that out if left to my own devices.

Many thanks. I can rest easy now.