Hi guys,
As I understand on this issue, you want to set a default price per attribute. As I recall on ps v1.6 I don't think those functionalities is already there. But to further the discussion, it seems like you need to create modules that manipulate the data structure of ps_attribute and add new column for default price then override the adminproductcontroller that allow ps to recalculate the impact price per attributes combination. Using these method you will be allow to manipulate the impact price of product combination but if changes happens on the attribute default price the previous created product with combination will not be affected except when you update it.
Best,
Mark Anthony Morales