I never owned the F75+ so I am not sure what processors it had. I have several F75's since I retired in 2010. The first 2 I had didn't have the BP (Boost Processor) so the deepest processor they had was SE (Default Processor). I could not tell any deference in depth for coin hunting.
The one I have now is the F75SE (Special Edition) and it is the all black. All I can see different from my first 2 is they added 2 new processors, FA (Fast Processor) which is very fast but not much depth. The other is the bp (Boost Processor) now it way deeper than the dE processor but it is slow. So I am 74 years old and slow so it is a match. My F75 has been in the closet for a couple of years now, I have been running the E-Trac full time trying to get the max out of it.
Bottom line I think they are all the same machines with just add on processors. Hope that helps,
Ron in WV