Hi. Yes. I'll tell you in a minute but first, Welcome to HAN.

You would have to have it in a lower gear than Drive in order to get it to rev higher, which I do not advise you to do by the way because it will probably do damage.
It's because of the way the tranny is designed to work. And I think the reason you have varying results is because of the terrain that you're driving on. I read somewhere that Acura put a special grade sensing thing in those auto transmissions.