ahhhhh..... now the penny dropped!
i completely missunderstood that....the first parentheses value pair sets a value-range, the second one is responsible for the relative positioning! and this way, it's more than easy to get a value range 0-1 for an xy pad. and more: you can set the range on the fly when you assign variables! look at this here, an xy pad where you can select between two retangles in the same subpatch with different value ranges:
xy_range_0-1.pd

@toxonic said:

....you can set the range on the fly when you assign variables!

what a pity, its seems, you can't assign variables to these values - i get a parse error!