I'm not sure why you think the defense would be entitled to the full report at the time the SBI results came back, since their clients weren't under indictment. If someone is tested, LE has to give that person (suspect) the results as they pertain to that person, but I don't believe that suspect is entitled to the full report in terms of other findings and results as to other suspects tested. The reason this is even coming up at all is because we have an indictment of some suspects for whom there was no match. The remaining parts of the report that don't pertain to a particular suspect are part of an ongoing investigation and surely should not be divulged to somebody who was a "maybe" because that person can then pass that information on to the public or even a party that the relieved suspect knows is guilty but whose name hasn't come into play as another possible suspect. If a truly guilty party knew there was no viable semen sample taken from the victim, then he knows he can deny any sexual activity rather than getting into a "he said, she said" dispute that it was consensual if he's ever named and tested, for instance.
Lord knows I despise Nifong, but I would have to agree that not giving the full report at that point was the proper thing to do if the prosecutor wants to protect an investigation. I don't say that was Nifong's motive for not giving the full report, but as a policy matter, it's the only thing that makes sense so I don't view it as sandbagging. The sandbagging came with the identifications and the indictments that fly in the face of the DNA results.