The scene with Andrews and Lightoller over the boat capacity I found problematical from an historical perspective, but understandable from a dramatic perspective. Cameron - for very obvious reasons - needed to make explicit the fact that boats were being sent away underloaded. The easiest way was to insert a piece of fictional dialogue - even if there is no evidence that such a discussion ever took place.
Sharon, where is all your evidence to prove that he had to go out of his way at all to make them look bad. Reading their testomony, they make themselves look bad - and look like liars.
I don't know if Cameron deliberately chose to portray the English officers in a more negative light, while presenting the Welsh-born and Scotish officers more positively, but this is the end effect - although, to be fair, Wilde comes across very well in his very limited role (one of my favourite depictions of an historic figure in the movie).
I do strongly disagree that their testimony 'makes them look bad' and 'like liars' - those brush strokes are far too broad. There are moments when they admit mistakes (e.g. Pitman not returning), or when their testimony reveals that they have made errors of judgement, but very few witnesses involved in a complex and controversial series of events, when subjected to lenghty and sometimes hostile cross-examination (in spite of the fact, as Senator Smith pointed out, that it wasn't a trial), who would find that their actions stood up as perfect. I don't think they look 'bad' - I think they emerge as human figures, in a desperate situation, who did the best that they could with the time, knowledge and skills given to them, and who for the most part acquitted themselves well.
Then, of course, we have the men who didn't survive to depict themselves as anything. Moody never lived to lie, tell the truth, illuminate his own actions as gloriously heroic or despicably cowardly - he just died. In Cameron's movie he is reduced to a figure who acts as a roadblock during the collision scenes - getting in the way with his fictional cup of tea - before, eventually, fading out altogether. We don't see the real man who, as the historic evidence suggests, worked until the last of the lifeboats was launched, refused a chance to leave in charge of a boat, quietly and diligently loaded passengers, and then died while still trying to save lives.