Washing Existing Concrete and Default Values

Has anyone tried to clean and lighten existing concrete to qualify for this credit? If so, what documentation did you have to provide to show that it was "suficiently cleaned and lightened to qualify for the default SRI value"? What process did you use to lighten it? Would pressure washing suffice? Did you know what type of concrete you had originally (gray, versus another color)? Secondly, have people had success entering default values from the Reference Guide for the hardscape materials or have you had to find values from your manufacturer?