I would add that it is time for you to use what I call "Spock-talk" with your H in those negotiations. Just the state the facts and stick with them. Normally it's best to avoid using "I" since H is one of those Jekyll/Hyde MLCers and anything perceived as an attack or slight against him will set him off on a spewing rampage.
Less wordy and more concise sentences help a great deal. It would be helpful if you can post your draft responses here so you can get the feedback before hitting the send button to H. This way you'll be able to head off any potential blowbacks or spewing at the pass. I should add here...'in the best possible way'. No guarantees here.
No guarantees here.