Frankly, I think NEW has nothing to do with sleep time, because we need Delta to renew ourselves and to make certain healing hormones (our brains won't make certain hormones unless we have delta waves), so even NEW may increase circulation and improve healing time and quality, it won't make us make more of the hormones, etc. I think that's more of a genetic crapshoot.
Mind you, I've greatly improved back problems with NEW, and it helps me beat colds, but I'm not sure if it can be used to replace delta sleep.