I didn't have a graph of the manual transmission. The first five gears are the same as our bikes. The sixth gear is an extra full step more, lowering the RPM's about 20%. If someone does not want to use the 6th gear, they don't have too.
I too think the same thing could have been done with 5 speeds and just spreading them out. But, there are others who will disagree.
The DCT put an extra gear in the lower speeds. I think it is more than needed. But, since it is automatic, it won't be even noticed most of the time.