I am trying to create a timesheet for my students and am running into issue I
am not sure how to solve. Any suggestions would be greatly appreciated.

The student are to work on a series of projects that take anywhere from 20
minutes to ca. 6 hours during a class period of 83 minutes. I want to be able
to keep track of two things. First, the time sheet needs to keeps track of
the total time spent on a particular project (possibly across more one day).
This total will be compared with a percentage of the time I think is
appropriate for that project and a then a grade is assigned. Second, is to
keep track of the total amount of time that is used toward projects (possibly
more than one in a single class period) and then compare this total with the
total number of minutes in the class period (i.e., 83) to determine "wasted"
time.

I have tried setting this time sheet up two different ways: "project based"
and "date based". In other words, I have been able to do each of these
procedures independently. However, I am having a mental block as to how to
set this up so that both would occur at the same time.

Please help with any ideas.