My LoR professors were American and British (Indiana, Princeton, Trinity College Dublin), so I don't necessarily think that was the issue.
I'm no longer in Korea and I'm working in administration at a small US university which has no foreign language support (so I can't improve my Korean). I've actually taken classes at Yonsei and Sogang previously, but I'm probably only TOPIK level 3/4 (haven't had the opportunity to take it).
Thanks for the information.