I had been toying for a few weeks with a 4.1mph power-walk phase following my speed phases. After last session, I decided this is actually just hindering my overall speed, because I don't cool down or recover breath appreciably at that pace. It only delays recovery. To actually recover enough to face the next speed phase, I have to slow down to, at most, ~3.7mph. Even at 3.7mph it takes AT LEAST a full lap to recover, often more like 1.5 or even 2 laps after a harder pace if I don't drop down to an easy 3.3-3.5mph walk.
In fact, if I can just alternate between 3.4mph warm-up/recovery and 5.4mph speed phases, taking no longer on recovery than I do on speeding, then there's my 4.4mph average. If I can do 2 laps at 5.4mph when I'm fresh, it should be a cinch to alternate laps.
Alarm went off at 7:30AM; coffee, vitamins and omega-3. Aforementioned egg+cheese and a large coffee ~noon; skipped my usual Subway, demolished a whole quart of electro-Tang with a couple children's chewable vitamins, a late supper of microwave burritos and bed by midnight.