The time to disconnect the HV battery is included in the manufacturer's time for each operation it is necessary (Head lamps, fog lamps, front bumper, etc).
The necessary time to allow the HV system to discharge is not included as they deem other operations can be carried out during this time so a separate allowance would not be applicable.
Time for health and safety preparation is also not included i.e. testing the gloves, testing the terminals, insulating the terminals, creating the boric acid solution. All these operations may not be required every time and can vary by job. An allowance would have to be agreed with your work provider if applicable.
Before carrying out any work on the High Voltage system be sure to follow all safety measures as indicated by the manufacturer and ensure you are appropriately trained to carry out the work.