I do oil analysis, but reading the results is not always straight forward. I had a sample come back with higher than normal silica (dirt). So I had my mechanics inspect the entire induction system, air filters, etc. It was winter and my flying wasn't in especially dusty places, nothing found, so.....
I took another sample next oil change, all is well.
No explanation, just some money spent for an inspection.
I also notice the results change with the type of flying you do. For example lean cruise will give one result, high power/rich training will produce another. It makes it hard to react to a questionable sample.
The other thing to note, while Blackstone, etc list the number of hours between changes I'm not sure they rationalize the contamination against the hours vs. the fleet averages. For example if you always change at 20-25 hours you'll probably always get better than fleet average results.