I am glad you are open to trying new ways. It is almost essential with a difficult child. Even if you find something that works - it might only work for 2 months. It is a constant re-evaluation process. It really kinda stinks!
Be sure to know that I in no way said what husband does is correct. It is different than what you are trying right now. It seems to get a better reaction from difficult child. Again, that could end tomorrow.
You already know that what you really need to do is get husband and you doing the same thing - every time. I think it will be easier to tell husband you will try his way first, but you could create a new way that you both can agree to try first - pick a time frame and then evaluate what is working and what is not. It is not traditional parenting that is for sure. Hence the reason we all searched out the site - nothing we were doing was working.