Splitting Employee Punches by Factory Shift

solution using list.generate to generate the shifts.  

Add Custom Column with this formula and then expand the column.

let
    punch_in = [Second Punch In], // update to punch in column
    punch_out = [Second Punch Out], //update to punch out column
    shifts = {#time(7,0,0), #time(15,0,0), #time(23,0,0)},
    start_of_shift = Date.From(punch_in) & 
        List.Select(
            shifts, 
            (x) => [ 
                a = Duration.Hours(punch_in-(Date.From(punch_in) & x)),
                b = a < 8 and a >= 0
            ][b] 
        ){0},
    generate_shifts = List.Generate( () =>
        [start = start_of_shift, end = start + #duration(0,8,0,0)],
        (x) => punch_out > x[start],
        (x) => [start = x[start] + #duration(0,8,0,0), end = start + #duration(0,8,0,0)],
        (x) => [
            shift_start = x[start], 
            shift_end = x[end], 
            hrs = Duration.TotalMinutes(
                List.Min({punch_out,shift_end})-
                List.Max({punch_in,shift_start})
            )/60,
            shift = Text.From(Number.Mod(Time.Hour(shift_start),12)) & " - " & Text.From(Number.Mod(Time.Hour(shift_end),12))
        ]
    )
in 
    Table.FromRecords(generate_shifts))