As Redwire suggested, you need to customize your drill table by copying the standard .dlt from the software and add an additional column to your drill chart with the additional countersink information. All the details on how to do it are contained in the .dlt file, the lines that start with a semi-column (;) are instructions.
For example, make a copy of the default_mil.dlt file in the software and make the following additions: (BOLD)
("Figure" "FIGURE" 7)
("Holesize" "SIZE" 15)
("Tolerance" "TOLERANCE" 15)
("PlateStatus" "PLATED" 10)
("NonStandard" "NONSTANDARD" 15)
("Quantity" "QTY" 6)
("USER" "SPECIAL MACHINING" 40)
; A column definition in ?ColumnDefinitions above can have "User" appear
; in the first field to indicate a column of user-defined data. The
; data is specified by ?CustomData definitions that are matched to holes
; appearing in the legend table.
( 129.1 "Not Plated" "248 x 100 DEGREES CSK, SECONDARY SIDE")
This will add the countersink information in the last column for all 129.1 mils Non-plated drills in the drill chart. I make the drill size for the holes that require a countersink unique by adding a number after the decimal point to avoid adding the countersink note on all 129 mils Non-plated drills that may be included in drill chart. See attached image for example of the drill table with a custom column based on the updated .dlt above.
I have used this additional column on press fit connectors drills where the manufacture recommends a drill size prior to plating.
Hope this helps,