[Piwoslaw]

Most of my driving is in flat terrain and P&G has helped me use less fuel. I haven't done an A-B-A-B test to compare P&G vs steady speed, but it is in my plans. Aeromods and higher tire pressure definitely help your glide in flat terrain, they also allow you to keep a steady coast down slight inclines where previously you would lose speed. Win-win.

I'm not sure if I remember the exact reason for this correctly, but here is what's floating around in my head:
My engine consumes 0.5 liters of fuel per hour (8.3 milliliters per minute) when idling. Coasting down from 70 km/h to 50 km/h takes about 10 seconds. Accelerating from 50 km/h to 70 km/h registers as roughly 8.5 lph (142 mlpm) and takes about 5 seconds. So, one pulse/glide cycle takes 15 seconds and uses 11.83+1.38=13.21 ml of fuel, or 52.84 mlpm (3.17 lph). Driving at a steady 60 km/h registers at about 3.5 lph.

I used semi-random numbers just for illustration, I don't have the actual data, but those numbers look right. The longer you coast compared to the pulse, the better the results. Downhill and/or lower speeds is where P&G is best, flat terrain is still good, unless you're driving a brick on the highway. Groar once remarked that P&G-ing at highway speeds (above 90 km/h, 55mph) is pointless, same goes for hill climbing.