Force Change Event in workbook

Please can anyone help with the following;

I Have a workbook with various named worksheets which I use to calculate perfomance based on Total No. of items handled divided by total labour hours used giving me a value for Items per Labour Hour. Depending on this value some cells are formatted in a colour in order to draw the users attention to it. I also have a summary sheet where some of the info from each worksheet is displayed. On the summary sheet there is a target value for items per labour hour. The individual worksheets code works fine but I cannot get the worksheet cells to reformat if I ammend the target value on the summary.

I have used the following code on the ThisWorkbook Change event

Private Sub Workbook_SheetChange(ByVal Sh As Object, ByVal Target As Range)

Dim ws As Worksheet
Select Case Sh.Name
    Case "ICE X 10", "CHINA", "COS", "ICEX12", "HEARTS", "gem", "CELERY", "STICKS" 'Excluded Summary sheet
        FormatSheet Sh
    Case "Summary"
        For Each ws In ThisWorkbook.Worksheets
            Select Case ws.Name
                Case "ICE X 10", "CHINA", "COS", "ICEX12", "HEARTS", "gem", "CELERY", "STICKS" 'Excluded Summary sheet
                    FormatSheet ws
            End Select
        Next
End Select
End Sub

and also
Created a module with the following code

Sub FormatSheet(ws As Worksheet)
    Dim i As Integer, nColor
    With ws
        If ws.Name <> "STICKS" Then
            i = 0
        Else
            i = 3
        End If
        
        If .Cells(22, 3).Value & .Cells(22, 4).Value & .Cells(22, 5).Value <> "" Then
            If .Cells(30, 16).Value < Worksheets("Summary").Cells(6, 10).Value Then
                nColor = RGB(255, 0, 0)
            Else
                nColor = RGB(0, 255, 0)
            End If
        Else
            nColor = RGB(255, 255, 153)
        End If
        
        .Range(.Cells(33 + i, "J"), .Cells(39 + i, "Q")).Interior.Color = nColor
        .Cells(30 + i, "P").Interior.Color = nColor
    End With
End Sub

Cheers
Colin