sampling method

[KiA]

has anyone done a test to take different samples from the same used oil to see how much of a difference sampling method makes?

for example towards the beginning, middle & end.

 

[Patman]

I've often wondered this too, but even if someone did do this, you'd have to wonder if the difference in results is due to the time of the sampling or due to the lab testing. In other words, maybe if you took the exact same sample and tested it twice, it would show different results. So how would you know exactly what is going on?

 

[KiA]

true. that too.
we tend to look at #s as absolute, even though they are +/- some.