Originally Posted by beergolf
That ratio is for mashing. You then sparge with more water to reach the boil volume.
This is true. In my previous statement I left out the sparge step. But if all aspects are consistent (including the sparge water volume), post boil volume is the same.
If i understand the question of the OP it was related to how the ratio maintains a consistent volume in both scenarios when more water is necessary for increased grain weight.