Version 66 keeps version 64's as-shot white balance and black level offsets; its word 661 is below where the sensor clips, so the white level stays measured from the data. Checked on 33 R6 Mark III files from 12 shoots: all now open with their as-shot white balance, black levels match the masked columns. Co-Authored-By: Claude <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_017JKdR4oZ3jRSPPwMLLTa2U