Immo coding can be done by a number of people, but I always use audi for immo full stop, as anyone could clone the keys whilst doing your cluster, believe me there is kit out there you can place inside the reader ring, it will read then code a new key with the same data, so immo@audi imho.
Mileage correction comes down to 2 ways, audi can do on new clusters or used with less than 100km's in total or they cant change mielage or there are companies that specialise in this & if the persons doing it can crack the encryption with there machines firmware, now when I did mine it wasnt possible, but we are talking just when the white clusters were out, but there have been new releases of firmware for the machines that do these newer clusters which I havnt revisited for, I know some correctors have said they now can change mileage on mine, not sure of the later ones MY10/11 as audi change often, but dont see why not, just have to check the part numbers thats all if MY10/11 have a new part number for the newer cars, then we know they've changed somehow.
Infact glad this thread has come up as its now helped me check for another mod if my cluster is ok for it.