A reason for the 'sixth' One: six is the biblical day on which humanity was made, and Neo is in a sense the first 'human'. He is certainly the first 'One' who defeats the system and establishes the basis for freedom. The seventh 'reloading' would then be a 'sabbath': a 'day' of rest, on which the war would be over, or at least paused.
- Suggested by Wes Howard-Brook