values

Why is the value in F9 positive? Based on your description and the other examples, I would have expected F9 to be -2.

Assuming F9 is in error, it looks to me that something like =SIGN(E4)*(B4-B3) should work for this. If you are unfamiliar with the SIGN() function, it returns -1 when the value is less than 0, 0 when the value is 0, and +1 when the value is above 0 (https://support.microsoft.com/en-us/...1-2dd0e916a1d8 ).

If F9 is not in error, then I do not understand the desired logic.