My formula is as follow:
L31=IF(OR(J31="",K31=""),"",(J31-K31)/J31). M31is the goal number.
I set a conditional formatting that if L31 is less than M31 the cell is fill
red and if L31 is greater than or equal to M31 it will be green. When J31 and
K31 is blank, L31 is appear green.

I have another formula.
L43=IF(OR(J43="",K43=""),"",SUM(J43:K43)). I set some condtional formatting.
However when J43 and K43 is blank, L43 turn appear as red.
Why the difference?

What I dont understand is