OK, another almost unanswerable question

Basic question would be...Are there specific distances a given rod weight should be expected to cast?

Variables...let's say 9'...average castor [or would intermediate be a better term]...

I guess another way to put it would be...How much farther can the same castor cast a 7wt vs say a 4wt?

Or will a rod one size larger cast say 10' farther?

Googling didn't help much but Al Campbell sort of alluded to the issue in this...

http://www.flyanglersonline.com/alcampb ... right.html