I have a problem.

Let's say my HCH averages 60 mpg during the pulse phase for let's say, one mile, and then I shut off the engine and glide for another mile. The mpg during said glide phase is...infinite mpg, since I got a mile while burning no gas whatsoever. However, the HCH computer surely can't average an infinite mpg number into the overall mpg. I theorize the mpg computer simply says to itself "the car burned x gallons of gas for one mile (during the 60mpg pulse phase) and burned no gas as it travelled another mile, thus it travelled 2 miles on the gas burned during the pulse phase, thus doubling the calculated/measured mpg for a 120 mpg average."

Now let's say my HCH averages 40 mpg during the pulse phase for one mile, and then I shut off the engine and glide for another mile. The average for the 2 miles travelled on the gas burned during the pulse phase is doubled for an 80 mpg average."

But let's say my HCH averages 40 mpg for one mile during a pulse phase, and then averages 120 mpg for the next mile during the glide phase. The average for the 2 miles is still 80 mpg, right? How?

How is it that the average mpg in these 2 examples can be the same? Is averaging 120 mpg during the glide the same/equivalent of infinite mpg for a mile while burning no gas at all?

Let's say the pulse phase averages 30 mpg for a mile, and then the infinite mpg glide with the ICE off for one mile doubles the effective/average mpg to 60 mpg for the 2 miles. But if the pulse phase is 30 mpg for a mile and the glide phase is 120 mpg for a mile, the average is 75 mpg, right?

How can it be that a glide at 120 mpg in this last example is better than a glide with infinite mpg? What am I doing wrong?

Bob