VBA code to calculate only changed range of cells

Hi all,

I am using the following code:

Application.Calculation = xlCalculationManual
    For Each Cll In Range("C24:J39,C41:R56,I7:I22,L7:L16")
        For Each TCll In Target
        If Cll.Address = TCll.Address Then
            Sheet4.Calculate
            Exit Sub
        End If
        Next TCll
    Next Cll

to calculate (update) a range of cells on sheet4 if changes occur. However this causes multiple calculations on the 16 sheets that reference these cells. Would it be possible to turn off calculation if there are NO changes in the cells?

Thanks for any help.