Probably SUMPRODUCT (across sheets) but confused due to complexity...

I have a report I need to run, and the constituent data is in two other sheets. Chart A contains a monthly report that references cited reports (A), date (B), and grade (C). In Chart B, it's a sheet that every department section issued (A) by serial number (B).

I need to write a report that counts instances of serials in A of Chart A, find and match them in serial (B) of Chart B, then look in (A) to see what department wrote them, then report them in Report C, column Number of Reports (B) and record the grade of each (C, D, and E). The same reports may get different grades from different graders. I need to count each instance as they appear in (A) of Chart A.

I want to capture the data from Chart A on a monthly basis, so Report C will be by month.

I hope what I'm asking even makes sense. I've enclosed a sample sheet of the data I want to run. I'm happy to answer clarifying questions.

Excel Forum is a stupendous resource for newbies like me. My sheets and charts have improved tremendously since I've found this board. The contributors are geniuses. This post is not cross-posted. Thanks in advance for your assistance.