The controller only sees the voltage difference. It doesn't care what changes it.
If the question was, "Sometimes I get a max current of 15.01 amps and another time, it's 15.02 amps, and now that I put a copper wire shunt in of the same value, it varies from 14.99 to 15.06 amps", what you wrote might be an explanation.
I think you're going to have to turn up your internet research skills to maximum to get this one.
And you might try turning DOWN your rude and unfriendly manner....
Try and improve on all counts, but I somehow feel that such surprises of sudden friendliness and good manners, are for you totally impossible! What a poor upbringing!
But please try to prove me wrong in the future!
Remember, you certainly did not supply enough information to make helping you possible in this case, remember, I gave you a further chance to improve your manners.........why do I bother in your case?
Possibly because of my good upbringing, and remembering the words of the Holy Bible:- Matt. 5 Verses 38 to 48, for example!
Andy