oil pressure light comes on at low rpms once in awhile. Little metal in the oil on 2004 BMW 330Ci

Took to a garage and they took the valve cover off found no problems, changed the oil pressure sensor and the filter canister did not fix the problem . Now the want to take the bottom pan off and look for concerns. Mechanic said the engine looks great so far. I'm confused and running out of cash, I do know the car runs great no leaks,no over heating. Looking for some direction Thanks

Asked by for the 2004 BMW 330Ci