What happens with your up-shift if you keep the power on is the clutch disengages, the engine revs rise (possibly hitting the limiter, won't harm it).
The gear-box selects the next gear.
Now the MCU starts to engage the clutch. It is measuring the speed of both sides, decides the differential is too great, so it signals the ECU which ******* the ignition, so reducing engine power a little.
The MCU continues to let the clutch slip while the engine revs reduce, gradually increasing the clutch engagement, finally fully engaging when the revs both sides of the clutch are close enough.
This gives a very sluggish-feeling up-change (accompanied by amateurish engine revving).
You should unload the gearbox while you flick the gear change switch, it only needs a momentary dip of the throttle. Time it right, you get a very fast and smooth change.
Goes for down-changes as well, but with a momentary increase in throttle; again, all you are really doing is unloading the gearbox during the change.
Now, on my Gen III YCC-S (unavailable State-side), it does properly deal with the engine speed. Its smoothest changes are made by not moving the throttle, smoothest of all if in touring mode, but I rarely use that. (Found that out when
taking a passenger.)