The subsonic 158 grain 9MM load is nothing new. IMI has been offering it for many decades. Fiochii also produces a 158 as do other manufacturers......
The 158 loading is designed to give more energy in subsonic ammunition (supressed use)
I began hand loading my own 158s about 20 or more years ago when the IMI supply dried up
Fortunately that fine ammunition is once again easily available for those folks that do not hand load
Now that more 165 grain projectiles are available for the 9MM cartridge I have switched to loading one of those bullets instead
With the 165 you load the 9MM to full pressure and still stay subsonic. That gives you maximum energy in a subsonic 9MM loading
I know they are really shiny