How to average individual scores when various works done have different work difficulty

Hello.

I'm trying to get the average of each person's work difficulty done for for different types of work. It's making it difficult for me because each person could randomly get whatever type of work and be graded on the difficulty level depending on how the work was done.

For example, Person 1 & 2 may be doing the same type of work but when it came to the point on how they basically did it & how difficult it was done, they could be graded differently. The only way i could simplify the raw data is to utilize a pivot, but due to the "sectioning-subsectioning", I'm unable to simply use the SUMPRODUCT formula to get the answer.

Hope the explanation makes sense.

Please see sample file attached.