And that right there, is pretty much it.I guess my question is..... Why ?
.45 is a very low pressure cartridge compared to other choices like 9mm and .40, and isn't going to be helped by compensation much at all.
You will get a sharper report and extra bulk (length), neither of which is helpful on a small carry pistol meant to be 1) carried concealed, and 2) unless your Shield solely is a range pistol, when it is used to defend yourself, will be fired without having time to put in ear pro, and could possibly be fired in an enclosed space.
No use making it louder than it already is for a miniscule recoil and muzzle rise advantage.
One of the things I like most about my .45 Shield is the very manageable recoil, and that's why I no longer have a 9mm or .40 Shield.
Maybe the reason you see comps for the other calibers and not for the .45 is that it's not something that anyone else deems necessary.