I have never attended a seminar in Missouri City, Texas.  The first seminar was held there in February of 2004, one week prior to the winter-get-together in PA.  I did not attend since I was somewhat "unemployed" and watching my nickels and dimes.  To the best of my knowledge, it was not attended by the HPOCA's current editor either.  But you would need conformation from them on that.  

I did visit Missouri City in March of 2003 for a one-day trip at the suggestion of the president.  It was to become familiar with the how subscriptions were handled there and to better the working relationship between McMillens and myself since I was working with them on a daily basis, but I've never been to their seminar.  - Sherry