What do you think happens when a heat pump go into defrost when its heating during the winter?? the short answer is that when it goes into defrost, its actually shifting into cooling mode and half of the heat strips come on to keep the thing from blowing snowballs inside while its defrosting outside. Dehumidification while in heat mode with the proper controls does the same thing. it shifts to first stage cooling mode and brings on half the strips to dehumidify. but don't worry about it because if its set up right, you'll never know that its even happening. it just makes your home comfortable.
There is no riddle to it. Reading a graph isn't going to answer your question either.
No resi system will cool down below 68 degrees without adding a freeze stat and defrost strips..... at least not without freezing the coil inside.
I am still trying to understand a couple of things here.... First is where your located...I must have missed that part, and second, why do you wanna turn the place into a walk in reefer, when thats not the purpose of a comfort system??