In your situation, if you are first and second, then it would be better for both of you to be clearly first and clearly second, i.e. instead of 94.4 and 94.3, you would have 95 and 94, so long as you don't lose your position, obviously. (unless, you are certain you and the other person will be able to achieve the same HSC exam mark, or within 1 mark, depending who is first and second)
If they are not first, then it doesn't really matter. They will probably send your mark in as the same as the other student.