The optional Apply Constraints As True Cost column works in conjunction with the Apply As True Cost column in the Constraint table and offers as an override for the general constraint level setting. It is only applicable for resources that participate in an appropriate constraint (i.e., it has a valid Constraint ID), and Apply as True Cost is set to True.  

When Apply as True Cost (Constraint table) is set to True for a particular constraint (emission, energy, or fuel) and Apply Constraints As True Cost (Resources table) is set to False for a resource in that constraint, the resource will not have the constraint shadow price applied as a true cost.

 NOTE: If Apply As True Cost in the Constraint table is set to False, even if Apply Constraints is True Cost = True in the Resources table, this option doesn't override the general setting for the constraint.

The default value for the column is True.