Currently, SACS uses 1 SPAN line to find all loading-related EC3 parameters (Cmy, Cmz CmLT, C1). Often, beams are restrained differently in strong and weak axes, indicating different SPAN lines should be considered for the different EC3 parameters.

See attached sketch example: while the full beam should be considered for Cmy, the segmented beam should be considered for CmLT and C1 (due to lateral restraints on the compression flange).