LUKE 3 humbucker volume question

I have a Luke 3 for few month , the full humbucker position seems a bit quieter than the others positions , in a volume point of view , but also in a “spectral” density for the sound ( though to explan ).
I had the late version of Luke 3 with musicman pickup.
I see there are already topic about this , but i don’t find an accurate answers, because trimpot seems to not doing balance between humbucker and middle and neck pickup.