iscsi: Another "silly" question: TotalAHSLength

[ISCSIPerson@aol.com]

Here is a silly question:

If the TotalAHSLength field is "only used in SCSI Command PDUs and MUST be 0 in all other PDUs" (draft-11 section 9.2.1.4), why is it included (instead of reserved) in the "other PDUs"?

Thanks in advance,

Greg A.