Degree Classification Algorithm

Hi,

So i was wondering if anyone understands this degree outcome algorithm.

My total credit for 2nd year is 120 credits spread over 4 modules.
There is 2 assesments in each module worth 15 credits each, meaning each module is worth 30 credits (4 x 30=120).
The new algorithm states the Bachelor’s degrees will be calculated using the best 100 credits at Level 5 (year 2) and the best 100 credits at Level 6 (year 3). Level 6 will be double-weighted.
This therefore enables the worst 20 credits at both Level 5 and Level 6 to be discounted before the calculation is made.
Given that our course structures are based on 30 credit modules, the discounting process will require certain modules to be ‘split’, with some credit counting toward the classification and the rest discarded. Our calculations will always discount the worst 20 credits at Level 5 and the worst 20 credits at Level 6.
Can anyone explain and calculate my overall grade for year 2, bearing in mind this information? And which grades will be discarded.
Grades:
Module 1- 68, 48 (62 overall)
Module 2- 64, 56 (59 overall)
Module 3- 74, 63 (69 overall)
Module 4- 58,56 (57 overall)

Thanks