I am trying to OLCI on CX for LAX-HKG (CX) then HKG-PVG (KA) - same reservation number. Since I am an Alaska member and KA flights cannot be accrued, I need to have both my AS and CX numbers.

When I booked the ticket, I had AS number on CX flight, and my MPC number on KA flight. Today, when I tried to OLCI, there is only one FFP number available for both flight. I didn't finish the check in process. However, when I looked at my reservation, both flights FFP# changed to CX and I could not change it back. Is there a way to OLCI with both numbers? If not, can the counter agent check me in with both numbers, or I will have to change the number at HKG for my connecting flight?

Is there any benefit of OLCI at all?