Timesheet differences

So sorry, I need the spreadsheet to look at the Codes in Column A and add Code 7 + Code 4 and that total to subtract 80 to give me the salary hours. Code 2 is always 0. The employee id is how you tell the employee total. Does that make sense? I have to do this every payday it is hard doing it the way I was so I was hoping for help. The total needs to be 80.

code7+code4-80=salary hours


I have been putting =80-the cell the hours are in but the 1, 4, and 7 codes are not always in order.

IF empoyee 15116 had 4 hours pto (code4) and 8 hours holiday (code 7) then the result for salary hours would be 68
I hope this helps, cause I need help.