Previous cobalt, chromium abnormal results, now decreased

Had a MoM right thr 2009,years later in 2021 after several exams, X-rays etc found metals increased, also had left done in 2015,but no metal parts in it..
Now 2026 cobalt has gone from 13.2 to present 7.9 this is a decrease!!
Also same for chromium
Lab error tho my tests have always gone to same place?
Surgeon always says don't go by numbers, pain more important
So now after 3 mike walk I have some pain, not bad but sitting for extended periods on firm surface does cause right upper hip, some discomfort, affects nerve to foot..
I'm 78 and surgery is big deal tho I'm told just a matter of switching metal parts but if more issues found at surgery time then extensive surgery.. with little pain I'm very hesitant but this metal lab results puzzling, Same with chromium 5.1 down to 4 now, why?
So numbers mean nothing?
I get echos, retinal checks, no real metal issues like in metallosis but fatigue tho I'm 78..
Have original knees,get cortisone once a year ..also torn rotator cuff but not much of a problem
Surgery is still big thing to consider,rehab etc..
Suggestions?? Thanks
Any suggestions?