methods said:Like Philf eluded to...
It is nice that they are "targeting" 3.8mOhms but in reality, a few hundred microOhms (3.8, 3.7, 3.6, 3.9...) is the difference of how the shunt is soldered.
If jack does it you get 3.5mOhms
If Jill does it you get 3.7mOhms
If you want accuracy you need to calibrate the shunt yourself.
-methods
I think they both must have had a go at it to get it down below 3.2mOhms.
Maybe I can mend it with some "vinegar and brown paper"