This isn't a very elegant solution, but perhaps it will work for you. Modify the the code below to suit your worksheet. Set link updating to manual. Run the code below. Changed cells will now be red. Create a second macro to delete the old stuff in column AA and reformat the formula cells like the rest of your workbook when you are through.
For Each targ In Sheets("sheet1").UsedRange.SpecialCells(xlCellTypeFormulas, 23)
If InStr(2, targ.Formula, "[") Then
Range("AA" & targ.Row) = targ.Value
targ.FormatConditions.Add Type:=xlExpression, Formula1:="=" & targ.Address & "<>" & "AA" & targ.Row
.Bold = True
.ColorIndex = 3