I can think of a couple of reasons why damage would opt to not send the motor back, and shipping costs isn't one of them.
What tweaks were made to the motor after received? I hear rego registration is a biatch for you boomerang chuckers down under.
Was Joe Gibbs
oil being used? A warranty requirement.
Maybe trying to fix something that isn't broken? Not at all uncommon in these here parts, damage seems like a guy who likes to fiddle with things.
Just say'in
Joe