I'd bump the hot spot to a minimum of 88 degrees which should raise your ambient temp to 80 which would be okay for the cool side. I don't like the temps getting in the 70's, but that's more my preference.
Also with the humidity, it's better to have it warm versus cool. I have some that stay on the hot side and some that stay in the middle and one or two that stays on the cool side. They know when to regulate themselves and all so I wouldn't worry about it.