It's ambiguous, I read it as the hashes being different for each customer out of a mistaken assumption that no two customers have the same password. A salt isn'

It's ambiguous, I read it as the hashes being different for each customer out of a mistaken assumption that no two customers have the same password. A salt isn't really a "key" for a hash function, because it isn't going to tell you by itself what the original unhashed value is, and neither will it by itself give you the final hash.