That's referred to as a brake boost, no? I've gotta try that - bet it puts you back in your seat lol.You can use 4a all the time. I use it in the mountains on the corners as it helps control body roll I think. Drives like a Subaru lol. Sport when you want to drive aggressively. I use sport mode and then select 4a, hold brake and give it gas until it builds boost for a good launch off the line. Anything super slippery like snow sand or mud I use mud and sand mode. Weather mode sucks and just Neuters the throttle. 4h only when off the pavement. Baja if you’re ripping in the sand, you can Baja mode then select 2wd to get it to do doughnuts. Your mileage may vary but I have done this since new and just passed 102000 miles.
Gotta admit I've never tried 4A since getting the truck but curious to try it now, and want to do a 0-60 run with the brake boost technique haha