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cloudcuckooland
If the airline you are flying with has dual FF fields (some or most do), use FQTV for FF earning, FQTS for status recognition. Warning, many agents are unaware of how to enter info correctly so there is a risk miles end up being credited to the wrong program.
If all you want for status is extra baggage allowance and lounge access then I'd have Asiana FF number entered but show your AC card at check in (for baggage allowance) and lounge (for entry). Be careful they do not swap your FF to AC number.