Did you align the IRS? It actually follows your route perfectly. Just did another test flight from EGLL to EDDV and I cant complain. There was one issue when the AP was overspeeding but I managed to get it sorted. Did an Autoland at the end with all the calculated speeds of the FMC. VNAV did not exceed its limits and LNAV , well I overflew every Waypoint and finished in EDDV what else can I say?! 8-)