A Note column in the Summary tab would be really handy! Either side of the Total (it’s such a large column) would do.
Here the manager can leave a note about any change of times or anything of significance that needs to be passed onto Payroll each week / month. It would need to have Manager and Payroll access / view only.
It would also be a great help to have a monthly total of hours for each employee – instead of having to manually add them.