Bringing someone onsite can be a time-intensive effort. This SOW assumes that won’t be necessary in most cases, but there might be times where the verifier may need to be onsite to confirm various building characteristics that can’t be confirmed remotely. An example is if a building has undergone a renovation that wasn’t well documented.
Generally, Optional Task 3 is needed if an owner/staff doesn’t have capacity to answer the verifier’s questions. Since the verifier is the one responsible for verification, it makes sense for the verifier to then get access to the building to answer their questions directly through observation and discussion with the onsite engineer or maintenance tech. Onsite staff may be needed to escort the verifier in this effort, and as a bonus the verifier might be able to explain to onsite staff what they’re looking for and streamline the process. This could help at other buildings, potentially reducing the verification effort for those buildings.