It adds 3 and subtracts 1 instead of adding just 1

Ehm so you've no timing error?

I mean not what it tell you while you compile (also if you can see it in the end because it tell you that all time requiring are met), but if you see some path in red in the compilation report (the window that open to you when you end to compile: on the left side you should see something like Timing Analisies: open it and see if something is red).

What about the:

"warnings on Timing Analysis Timing Analysis due to pulse width violations"?

have they vanished?

Now I'll have to go home, good week end.