Cam Duration Vs. Usable/Used RPM Range

So i have been thinking about duration in a slightly different way. I know you usually only want the minimum amount of duration to achieve a rpm shift or redline.

Now if your shifting at say 6500, when you shift it drops to:

1-2 shift 3850rpms
2-3 shift 4480rpms

Lets use a 500RB, 4.15 stroke motor as our model. So if your running a 240* @ .050 cam and (3000-6000, 6500 redline ( Crower 32309 cam) and say the Crower 32310 (3500-6500, 7000redline), which would go faster.

It seems to me if your shift point never dropped below your peak tq it would go faster, even if the cam was bigger. Im just looking at this and curious.