What is the difference between using IF and IFF in a formula?
IFF only evaluates the path of the formula that meets the stated condition whereas IF evaluates both parts of the formula. When creating formulas with IFF and IF, the syntax is the same. I would recommend initially creating a formula with an IF statement to make sure that both parts of the formula are valid and test both paths. Once you have established and tested the formula, if your formula is complex and taking a long time to calculate, then try IFF to see if this improves the performance. Sometimes using the IFF statement will help you avoid circular references in formulas where you are referring to time.