The fact that they're the same difference apart brings the point home I think.
The fact that they are the same difference apart, means that Oda put thought into it.
I've always said, height is a dominance thing. Taller individuals are seen stronger, more imposing etc. if even subconsciously, the fact that Oda is purposefully giving 1 cm more between two individuals which he can easily just give the same height to, means something.
It's not the end all be all, but height scaling has some merit to it, if only at a psychological level.