Mac...you've nailed it.

What I wanted to add, though, is that I think jackets have gotten progressively longer over the past century+. There was a thread about doublets sometime last year that highlighted the fact that the waistline in many 19th century doublets (as based on photographic evidence), was somewhere around the elbows. If you look at many modern PCs, they ended about 3-4" (or possibly even more) lower than that. I think the same might be said of Argylls. They may have started above the sleeve, crept somewhat lower over the past 100 years...and now are getting longer still. Just a theory...I have nothing to back it up.