Sorry, 2atlow8, but I think your memory might be failing you here. I believe Dr. Henson taught SS at Southside until the very end in the late 80s. He may have resigned as a deacon but I know for a fact that it was not required that faculty members and students leave Southside at that time. There were a great number of faculty members involved in the ministry at Southside in many areas including music until that time. There were students attending Southside all through the 80s.
One of the main problems with the interracial couple joining is that the couple apparently came down different aisles, as if they were hiding the fact that they were married. I have checked with a couple of sources at Bob Jones who do not recall BJIII ever saying anything about that in chapel. They did verify for me that SS was not put off limits until much much later than that.
The break at Southside with fundamentalism came over philosophy of ministry, which was first manifested in their musical choices. SS was put off limits in the late 80s after they sponsored a Steve Green concert that prominently featured the song "Let the Walls Come Down," a song that encouraged the breakdown of doctrinal barriers for the sake of unity (something that is an anti-fundamentalist as you can get). BJIII played the entire song in chapel, and explained that he played the entire song so that no one would think he was taking it out of context. That is one of the few chapel messages that was never available on cassette tape because of the copyright issues. In the chapel service, Dr. Bob explained that he had met with Handford on several occasions over a long period of time and tried to reach an accord about it, but Handford resisted. At that point, he said that students and faculty would no longer be allowed to attend while maintaining their association with Bob Jones. That was, I believe, 1989 or 1990. At one point, I did have a tape of the message recorded from the radio program "Chapel Hour" that played on the radio in the Greenville area every night. The radio program announced that tapes would not be available.
The separation did not have to do with following a particular interpretation of the Scriptures. It dealt with Southside's willingness to tolerate association with doctrinal deviancy on the the matter of doctrinal integrity and scriptural obedience. The direction of SS in that last 15 years has verified this. Interestingly enough, many people note the the leftward movement at Southside happened soon after John R. Rice died. Handford's wife was Rice's daughter. There are some people who have suggested that Handford was unwilling to make those moves so long as Rice was alive. Once Rice was dead, then things started to change.