With you particular setup, 390 is an ideal setup IMO. I have shot deer shooting much less draw length and weight and heavier arrows out to 40 yards with complete pass throughs. I wouldn't worry too much. You already answered yourself, you shoot it well and have a lot of confidence in it. So whats the problem?

I think we are getting WAY to wrapped up in KE and arrow weight. If you recall, Fred Bear killed many animals all over north america with a 45 pound recurve and ceder arrows. Do you think for a minute that his bows were producing any where near the KE we are now?