Our firm has completed this pilot credit a few times now, and we seem to learn something new every time we get review comments back. 

The first important lesson we learned is that in the matrix, you must clearly list out each of the categories, even if you need to write "No impacts or not applicable". I think originally we had assumed that if the section is not applicable or if there are no impacts in that category, we could omit it and it would be assumed. It seems like the LEED reviewers want you to explicitly address every impact, even if not applicable. 

Another lesson that we learned is that it is useful (if not necessary) to include an additional line at the bottom of the matrix under the "functional unit, lifecycle scope, and supplemental information" section titled "Additional Installation Materials". We aren't sure why this isn't included in the matrix worksheet on the USGBC website, but this section allows us to list any other materials that may be needed to install a product, and make it clear that we are only analyzing the product that is chosen for the credit, NOT the other installation materials required.