I personally think that it is a good idea to train your dog to do what it is that you want them to do. If you want them to get up onto something, then train an up cue. If you want them to get down from something, then train an off cue. Train it using positive methods so that the dog never thinks of the off cue as a bad thing. It is a cue and not a command. It is a request and not an “or else”.
Train your dog to do the behaviors that you want him to do… Reward the behaviors and practice the behaviors so that they are fluid and understood by the dog.