Check Each Cell In Range For Value & Put Text In Offset Cell

I'm trying to look at a value in one column (Column A) and if it matches a set of criteria, I'm trying to change the value of another cell 6 columns to the right.(Column G) I've been trying for a couple of days now to get this working, but to no avail. I've tried to modify the code below that I've found on this site but can't quite figure out what I'm doing wrong.

Sub RatingsFix1SP()
Dim FindWhat, rngCell As Range, i As Integer
FindWhat = Array("BB", "B", "CCC", "CC", "C", "CCC+")
For i = 0 To 3
For Each rngCell In Range("A2", Range("A" & Rows.Count).End(xlUp))
If InStr(rngCell, FindWhat(i)) <> 0 Then
rngCell.Offset(0, 6) = 0.15
End If
Next rngCell
Next i
End Sub

To try to clarify a bit: If column A in the attached spreadsheet has a rating code of BB, B, CCC, CC, C, or CCC+, I want the Haircut % rate in column G to be 15%. It seems the code that I'm using changes the % rate to 15% if any "B" or "C" shows up in any part of the string in column A.