I need a formula that will help me produce the correct answer in this
scenario: If Revised forecast is <0 then Forecast - Actual, if Revised
Forecast is 0 then Revised Forecast - Actual

Forecast
360

Revised Forecast
600

Actual
10

Variance
590

This formula is not working -
=IF(D13<"0",SUM(D4-D22),IF(D13"0",SUM(D13-D22)))