this is just the internal balance of the composer which has 0 as the maximum sound and -127 as no sound. Those balances remain constant within that variation, fill, intro etc without affecting any other variation, fill, intro etc. They are then globally modified externally by the balance in the mixer/part setting but keep the relative internal balances.

In the same way page 2 has a parametric tone control for that individual part in that individual variation, fill, intro etc. That frequency balance remains constant relative to the other parts in that variation, fill, intro etc, and relative to the other variations, fills, intros etc. This is independent of the external mixer parametric tone control or total keyboard parametric equaliser which are all additive to those internal effects.