mlr, double-clutch is used for down changes, not up changes. It is designed to match the speed of the engine to the speed of the gearbox. Between steps 2 and 3 (while clutch is engaged, but gearbox in neutral), you would also give a blip on the throttle to bring the engine revs up over what they were when you commenced the down change, so the the engine is revving fast enough to match the road speed. In most modern cars with healthy synchromeshes, it is not actually necessary to release and re-engage the clutch in the middle part (steps 2 & 3 - what happened to 4?), but simply "blip" the throttle. This is commonly referred to as "heel-toe".
Hamish, if you enjoy bouncing the engine on the rev limiter on every (up) gear change, then by all means go ahead and flat shift. Unless you have the supporting electronics, I would strongly advise against the practice.