[bestclimb]

How does the app derive the cost?
That is nearly 1.5 cents difference in cost per mile, going the wrong way.

11.8/35.4=.33 gallons used
.67/.33=2.03 dollars per gallon
.67/11.8=5.6 cents per mile at 35.4mpg

8.4/44=.191 gallons used
.60/.191=3.14 dollars per gallon
.6/8.4=7.1 cents per mile at 44 mpg

My guess based on the assumptions that the fuel mileage and distances are accurate...is that it is calculating the cost per mile over the whole tank and mpg over the trip.

for example if you reset the unit. drive 11.8 miles at 35.4 mpg. It calculates mpg and cost per mile and multiplies it by 11.8 comes up with a number for the cost of the trip

then you drive 8.4 more miles at 44 mpg it calculates the MPG over the 8.4 miles but the cost per mile is now calculated over 20.2(sum of the two trips) miles at an average of 38.8mpg this cost per mile is then multiplied by 8.4.

ps It's late check my math