Hello Paul,
You may not be KSW, but Seo , In Sun is not Hapkido - unless he wants to flaunt his first dan from Choi, third dan from who knows. Sorry, but he cannot have it both ways - said he was what, 9th, 10th dan KSW for more than 20 years, now poof, Hapkido.
No, what we are talking about is verifiable lineage - not just a collection of techniques - if that were the case, then why not just study from video tapes, then call yourself whatever rank the tapes leave off at? Simple, that is not a viable way to learn a martial art.
Your instructor may not be learning or have learned a KSW curriculum - but the ranking organization he is with is headed by a KSW ranked person - therefore making Hapkido rank from that organization questionable.
As alsways, just my opinion, we are talking lineage and rank validity here, not how hard someone trains or how good their technique is.