I worked in engineering for twenty years in metal fabrications .Now just my 2 cents i think 0.3mm run out is a very tight tolerance to be quoting on a 19" alloy wheel .I would thoroughly recommend the next member to have this problem to challenge the person to show you that at least the replacement was to spec before fitting
If it doesnt come up to spec ask for a further excuse as this is shall we say mythbusted
I am betting the service managers wish this was resolved as well and BMW proberbly want a way out as well without lossing to much face