Employee Timesheet; calculating +/- hours worked

Thanks for the help. Really appreciate it. I have a two more questions.
1. would it be possible to have the plus/minus columns in one?
2. Column "I" is "comment". I want a 8.5 hour day to be automatically entered in columns B,C,D,E, F (8:00;12:00;12:30;17:00:8:30) when I put either "Ferien" or Frei" in the "I" Column.