yes indeed, if you do a rate one turn to the right the ADF needle will have +10 degree error when established in the turn.
This is a geometrical error, imagine the ADF loop under the airplane, as you bank you change the antena position, also you change the magnetic environment around it (engines, wings going in the way and deviating signals).
It seem that in some airlines sims it is reproduced in other it is not, it makes a big difference to have a needle pointing to where you should stop the turn or to have to substract 10degs +-wind etc
I'm really surprized this has not been implemented in FS nor in FSX.
This is what I figured out by writing 0 to the offset.. sometimes I read back 0 sometimes not, the FS needle never show 0..
thks for your input