Broken function in tc.py. It runs but does not calculate _sum_time correctly. If tworked is > .1, funky things happen.For example, in the job table.. "worked" held 0.2. When .2 was supposed to be added to it, .2 was written again.I suspect my logic is incorrect but I can't find it. Help please?

tc.py

def clockout():
    """
    Clocks user out of project. Prints time_out (now) to clocktimes table for whichever row contains the same
    p_uuid created in project_start().

    :rtype : object
    :return:
    """
    if status == 0:
        raw_input("You're not currently in a job. Press enter to return to main menu")
        main_menu()
    else:
        global status
        global start_time
        global tworked
        _sum_time = 0

        sel = session.query(Job).order_by(Job.id.desc()).first()
        job_name = sel.name
        job_abbrev = sel.abbr

        now = datetime.now()
        print '\nStopping {0}, project ID {1} at {2}:{3} on {4}/{5}/{6}'.format(job_name, job_abbrev, now.hour, \
                                                                                now.minute, now.day, now.month, now.year)

        # Get difference between start time and now, and then convert to tenths of an hour.
        diff = datetime.now() - start_time

        time_worked = float(round_to_nearest(diff.seconds, 360)) / 3600
        if time_worked < .1:
            time_worked = .1

        if debug == 1:
            print("Variables -- Start Time {0}. Current Time: {1}. Diff: {2}. Time: {3}") \
                .format(start_time, datetime.now(), diff, time_worked)
            print('diff.seconds = {0}').format(diff.seconds)
            raw_input("Press enter to continue.")
        print ("Enjoy! You worked {0} hours on {1}.").format(time_worked, job_name)
        raw_input("\nPress enter to return to main menu.")
        status = 0

        # Update Clocktime table with time out and time worked.
        session.query(Clocktime). \
            filter(Clocktime.p_uuid == p_uuid). \
            update({"time_out": now}, synchronize_session='fetch')

        # Something is going on with this code or with the _sum_time += i.tworked below.
        session.query(Clocktime). \
            filter(Clocktime.p_uuid == p_uuid). \
            update({'tworked': time_worked}, synchronize_session='fetch')

        # Get all rows in clocktime for current job, by p_uuid and then sum these tenths of an hour.
        tworked = session.query(Clocktime).filter(Clocktime.p_uuid == p_uuid).order_by(Clocktime.id.desc()).all()

        for i in tworked:
            _sum_time += i.tworked
            if debug == 1:
                print("Debugging: sum of time for {0} is {1}").format(i.job_id, _sum_time)
                raw_input()

        session.query(Job). \
            filter(Job.p_uuid == p_uuid). \
            update({"worked": _sum_time}, synchronize_session='fetch')

        session.commit()

I think issues begin in line 47.