Loop Not Completing All Loops

Im using the following code to assign numerical values to words in two columns, then multiplying the values together and painting a cell with a specific color assigned to the final number. The problem is it wont do this past row 19

mLastRow = Sheet3.Cells(Rows.Count, "I").End(xlUp).Row
For m = mLastRow To 5 Step -1
' assign numerical values to the words in these columns
e = 22
r = 23

' Give Extent a value
If Cells(m, 9) = "Minor" Then
Cells(m, e) = 1
End If
If Cells(m, 9) = "Moderate" Then
Cells(m, e) = 5
End If
If Cells(m, 9) = "Serious" Then
Cells(m, e) = 8
End If
If Cells(m, 9) = "Critical" Then
Cells(m, e) = 10
End If....................................