Delta T
Your operations manuals(s) should outline the purpose for the logging of ICUS from the right seat.
If it says something like "because the regs say we can" well fine. If it is something more specific (like the examples I have given) then I am curious as to what they may be. The reason, is because I am doubtfull that the logging of ICUS from the right seat would be carried out without some sort of due process. The justification of that process is usually outlined in some form of documentation.
If you don't know, then fine. If you do, I would like to know.
That's all!