I admit, I am not a fan of 4A and as such, have not messed with 4A in the Raptor. The last couple of Fords that I did use it on were a 2005 expedition and that sucked. On a slippery road (snow) it would let the rear wheels rotate about 1/2 a turn before engaging the front. Just enough to make the rig break loose and try to spin out. No problem in 4H. Second was the 2024 Edge we had for a short time. 4A in that seemed to work just the opposite. Example, coming up our snow covered driveway, the front would spin out with little power to the rear resulting in the damned thing going sideways in the drive and stuck.
In summary, in 4H, front and rear are always in sync except when you choose a different path for them such as a sharp turn. As for the new Explorer we replaced the Edge with...so far off road has been great and I have hopes for it this winter. As of today, we are just weeks perhaps days from snow so I will know for sure if it can manage its 4A better on slippery stuff.
You do have me a bit curious though so when the snow flies, I may try 4A in the Raptor.