@martijn Hello! I understad, but over the Atlantic (and desert) I ended up far way from the point too. I red when the CDU doens't capture automatically (in bottom screen) the nearests VOR's (150NM...200NM signals) because is far from them, the accuracy, in a long leg tend to decrease, the IRS system makes kind of a triagulation with those VOR's. Not sure with IFR points... But when I asked "Am I right?" was for the specialists to awnser. The airplane doesn't have GPS as you know. Don't know if the "problem" worsne more with latitude or longitude. I belive, anyway, someone can explain you much better than me. Best!