Dear @eleeeel,
Thank you for your message.
Could you be more specific on the nature of the discrepancies that you observe when you mention: “higher reflectance of the 12, 4, 5 or 6 S-2A bands ?”.
As mentioned in S2 Processing, since Processing Baseline 04.00, the Level-1C radiometry has been harmonised after alignment of S2B on S2A.
If you observe discrepancies in Level-2A products this may come from the atmospheric correction as explained in Sentinel-2 tiles ND.
Cheers,
@Sen2cor_dev_team