Hello SeenFresh,

The problem is in the ANDing. You have a condition that is ANDed with the negation of itself (highlighted in red). This prevents the AND from ever being true.
. 
f Not IsNumeric(Cells(iRow, iCol).Value) And Not Left(Cells(iRow, iCol).Formula, 10) = "=SUBTOTAL(" _
        And IsNumeric(Cells(iRow, iCol).Value) And Cells(iRow, iCol).HasFormula = True Then
Sincerely,
Leith Ross