I spoke with Earl regarding the cost differences indicated for the Calpine -Topock interconnect.
The project files were discarded when the E&C Group moved to 3 Allen Center due to lack of storage capacity.
But Earl recalled that Jim Tucker said that the scope change was done at the request of Marketing which explains the two work order forms that you have.
E&C does not initiate project scope changes unless directed.

Calpine Cost Estimates