User can execute the same SQL code in both versions, however in 12.8 and 12.9, the data extract will not perform function calculations when doing a LookUp in Excel. Instead of the calculation being returned, the function itself is returned upon execution of the function.
Toad 12.6 works fine with functions, as one would expect any Excel spreadsheet.
User has both Toad 12.6 and 12.8 installed the 12.6 extract works fine with the Excel LOOKUP feature.
This appears that Toad for Oracle 12.9 may have a data export issue when doing trying to do a LOOKUP value with the exported 12.9 data.
This did not happen in 12.6