I hope you didn't get the problem clearly.
Calculation of "Rank" = Formula KF defaulted to 1 [Property: "Calculate single value as" -> Rank]
The problem is the Rank column definition is "Calculate Single value as".
So while the Formula: [Calculation of "Sal at Index Position" = (Rank == Index) * Salary] executes the values of Rank column is not 1,2,3,4 and instead just 1,1,1,1
Neverthless, you dont need the below "+ ..." part in your suggestion, since if the condition (rank ==index) will return 0 (false cases) and hence the salary will automatically become 0..
Is there any way to bring Rank column as 1,2,3,4 etc. and then it should be used in the calculations.
Regards,
Chathia.