Agency did not err when, on remand, it discounted extrinsic evidence that the court had held to be ambiguous.
Relevant date for assigning cost responsibility for a power network upgrade might reasonably be the date of the execution of the agreement to join the network.
https://www.cadc.uscourts.gov/internet/opinions.nsf/C8F18CF446B7250D852582A600522CF6/$file/16-1261.pdf
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.