the formula that I am trying does not return the results that I need.

=IF(C16<="14-Sep-05",SUM(F16*$S$1),IF(C16="15-Sep-05",SUM(F16*$S$2)))

Cell C16= date
Cell F16= Kilometers
Cell S1=0.37
and
Cell S2=0.40

The result I am getting is for the first part of the formula and not for the
second part when the date is greater than or equal to 15-Sep-05.