Question about OOTP

[CK Campbell]

New to this list, so I don't know if you've covered this or if I could
possibly locate it on yahoo, but...

In the climactic battle scene, Sirius calls Harry "James" -- it's not in the
book that way.  Does anyone know if Gary Oldman (or anyone) has discussed
the decision to do this?  Was it Oldmans?  Or perhaps a directorial or
writer's decision?  It adds a whole new meaning to their relationship that
he does this.

Thanks, Carolyn