Oh cool, I'm just days away from his testimony (doubtfully I'll feel as excited while watching it lol). Your memory is correct about BN, it was obvious he had little experiential knowledge about the vast majority he was testifying to, in my mind, if you (in this case BN) can't explain something you know to someone who doesn't (his constant complaints to JM about not understanding computers) then you really don't understand it all that well yourself - his condescension just seemed to be a cover for his own lack of grasp of the issues and not being able to explain the results he got.
I can't help but suspect that BN's lack of clarity was at least partially intentional. It seems to have been a defense strategy which they spread across several of their witnesses. Like Fonseca, when the defense was questioning them they had no problem giving clear concise answers, but on cross, facts suddenly became more nuanced, and Juan was 'missing the point' with his questions. BN presented himself as a consummate professional, eminently qualified for this type of work, but when Juan pressed him, suddenly anonymous assistants had done the actual work and the facts became lost in the obscurity of someone else's responsibility. If they had been equally incompetent and dense for both sides it would be one thing, but when it's so obviously biased towards one side, that's a strategy. The only logical reason for such a strategy is that the facts were not on their side; there was no damning evidence on the computer, and Travis' actual behavior did not back up any of their claims in that regard.