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I've been thinking about this, too.
If we assume the "default" setting (for highway travel, anyway) is the "cruise control" approach, then motorists strive--either by CC or manually--to maintain X mph, regardless of road grade.
Then "alternative setting #1" is DWL: to the greatest extent possible, maintain a constant throttle setting, while allowing speed to fluctuate. This results in LESS vairiation of throttle, and is touted as +FE.
"Alternative setting #2" is EOC: to effectively "pulse+glide" the terrain, by using the uphills as your "pulse," and the ensuing downhill as the "glide." Since this involves 1. zero throttle downhill, and 2. all your throttle on the uphill, this results in MORE variation of throttle, and is touted as +FE.
So, the message seems to be "just don't drive like a cruise control, and you'll get better FE," which seems to stretch the limits of credulity. On the other hand, plenty of accomplished hypermilers use DWL to get better FE, and I don't want to discount their experience. So, I think perhaps the solution is:
Use DWL for short, rolling hills where one can rely on thier momentum to carry them over. In other words, for the short "whoops" in the road, better to DWL and allow a small fluctuation in MPH.
Use EOC for sustained up- and downgrades that are too long and/or steep to count on momentum. In this environment, DWL is insufficient as a stand-alone option, and the terrain seems to be "strongly encouraging" an EOC alternative.
"Anticipate" transitions to up- and downhills in a way that a CC can't. In other words, as you crest a hill and see a long, sustained downgrade, just EOC right there (conditions permitting) instead of accelerating to get back to "cruise setting" before descent. After all, why use gasoline to get up to speed when you can wait 10 secs and get gravity to do it for you?
If I've misunderstood the issue, please let me know, but this seems intuitive righ now.
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