Final year grades

I am going to University of Greenwich. The university takes the best 90 credits from 3rd year.

University regulation:
The class of Honours will normally be calculated on the grades achieved in stages 2 and 3 of a programme in the ratio of 20:80. Aggregation of grades to obtain the class of Honours will be based on averaging the full spread of grades in Stage 2 to obtain 20% of the final grade and the average of the best 90 credits of overall module grades in Stage 3 (Level 6 or above) to obtain 80% of the final grade [20:80].
Does anyone know how they take the best 90 credits? I asked a guy who recently graduated. He said, the university takes the 2 best modules (15+15)credits and the final year project (60 credits). Does that mean, I have to just pass the other 2 modules?