Pulse & glide with diesel?

[GasSavers_Brock]

Ok I have been doing some runs comparing pulse and glide to flat out driving. It is darn near a wash. Maybe I am doing something wrong? My normal trip is 11 miles all in a 35 mph zone. I often leave work late (after midnight) and have no traffic. So I have been alternating between pulse and glide and straight driving. My overall speed ends up being the same which surprised me.

Straight driving I set the cruise at 35 and go, when I get home on scangauge the trip overall mph will be 30 mph with right about 90 mpg. The next night I run pulse and glide, getting up to 45 and gliding to 30. Again overall trip speed on SG is 30 and mpg is the same at 90 mph.

I could try gliding to 25 mph, but that would surely slow down my overall speed, which would increase my mpg, but I am guessing slowing down 1 or 2 mph in straight driving would net the same gain.

Maybe this could be because diesels run more efficient at lower loads, but I wanted to make sure I am not doing this wrong. Thoughts?

I guess I could do the same test in the van and see what happens?