Yes, we took that into consideration when I turned mine down. It’s why we only went about 10* down.I do have a suggestion that may be helpful. A significant downside (no pun intended) to downward pointing tips, is that the exhaust causes any road debris to become air born. Dust, sand and small gravel gets blasted into the air which is very annoying to other CACCs traveling next to or behind you. you.
I wear foam ear plugs which are very cheap, comfortable and effective in protecting my hearing. The only exception was driving next to Elder or Jack May when they were running with dumps.
I did in ~2007. I was very pleased.