Hypermiling...
I understand the def, but it is off the mark for most of us X owners, imo.
Few of us drive around with raw eggs under our feet, tires pumped to 45 lbs, skinny azz tires, coasting on downhills, sweating making the next 3 sets of traffic lights, etc.
Fwiw, that 568 I got on one tank was with 19" style 132s fairly wide azz tires, and making a normal haul azz one day drive from our NC Mtn Joint to NJ, to see the kids.
Just happened to catch a cool day with little A/C needed, until we neared the destination. Light traffic, no construction or accidents and few revenue cops for that 650 mile run...
Few of us are driving around in 5,000 lb cars chasing an extra 1/2 mpg to save dough or prove any point...I have more dollars than that under my couch cushions.
I do get a chuckle out of my Vette which can get 30 on some day long cruises, if I am lucky conditions-wise, and does do 28+ all the time on highway driving. But, weight or the lack of, and a very overdriven 6th gear ratio, coupled to a very powerful V8, are the key; not my 'driving'.
A shot I've posted before: a cumulative mpg shot after ~10,000 miles in a cross country trip. The arithmetic per tanks provided for a lower number of ~29+ at that time. I was not doing any 'hypermiling' at any time during that trip.
Back to normal driving and reality, here...
GL, mD