What do you think could be happening?

Okay. I'm getting better at doing the ILS approach from Reno NV to San Francisco but one thing I noticed the past two times when I'm on the approach (I'm on both Localizer and Glidescope) and I can see the runway, I've noticed that I'm always too far to the right. Usually about a mile or so too far to the right. By this time, the Autopilots are both active (Autoland on) and so it's pretty much hands off. So, I'm not flying the approach manually - it's the FMC. Why would I always come in too far over even when the localizer shows I'm lined up center? something amiss in the simulator? I have the latest AIRAC file. It's happened twice with the same destination airport of KSFO.

What do you think?

Here are the specs:

FSX - SP1 & 2
Addons - Airbus Vol. 1 (flying the Airbus 31😎
FDC Live
Flying the ILS, following the ATC only upon final
Vista, 32bit

Here are my steps:

1. At the departure airport; sitting in the cockpit, I program the MCDU - Importing the flight plan (Reno to SF), assign runways, performance info - Vspeeds, alt, flaps, etc;
2. Turn on engines;
3. Arm spoilers, speedbrakes; flaps for takeoff; Takeoff test on ECAM.
4. Contact ATC to get the departure runway; confirm this runway in MCDU;
5. Get taxi instructions from ATC; taxi the jet to the runway;
6. Get takeoff clearance from ATC; Take off - vroll all that stuff; Gear up; fly the heading of the runway; flaps returned to 0 during climb; Autothrust activated automatically;
7. Turn on Autopilot; Heading can be controlled by me or I can allow the Autopilot to manage it - generally this isn't all that crucial as long as I watch the flight path on the Navigation Display(ND);
8. Top of Climb point is reached on ND; Cruize Altitude activated;
9. Eventually I will reach the Top of Descent point; at some point the ATC will give me my first instructions to descend in altitude; this will continue until I'm just a few miles from the destination airport;
10. ATC will give me a heads up by saying something like "expect initial vectors for runway xyz.." At this point, I'll turn press the ILS button on the glareshield. Turning this on only displays the ILS frequency information in the lower lefthand corner of the Primary Flight Display (PFD). But it will only display if I've receipted that signal. I also go to the MCDU to confirm that the arrival runway is programmed in because many a time, the ATC has changed arrival runways from what I had programmed in before takeoff. If they changed runways, you'll need to change it in the MCDU.
11. Once, I see that the ILS runway is the same as what the ATC instructed me to, then I can continue to watch the ND. Expect to see "D symbol" point. The little magenta D. When you get just about over it or within a mile or two of it, you need to open the MCDU again. And Activate Approach, Confirm the Activation. Doing this will cause the airliner to slow down.
12. At this point, continue to watch the PFD for the ILS information to appear. At this point your airliner is probably about 20-30 miles or so from the arrival airport. Keep watching the speedtape for the equal signs which indicates that you should start lowering the flaps in single increments, slowing the plane down further. Arm ground spoilers; Set autobrake to MED.
13. ATC will say something like "cleared for ILS runway xyz, maintain xyz altitude until established on localizer". Press the LOC button on the glareshield. Watch the annunciator on the top of the PFD and the Localizer display as well; it will display whether you're too far to right or left of runway;
14. At the top of the PFD, the annunciator will display LOC or LOC* which means that you have picked up the localizer signal. At this point, I press APPR button on the glareshield. (sometimes the LOC button is pressed before the APPR)
15. If you wish to autoland this Airbus, you can also press the second Autopilot button.
16. Lower gear; at this point, you should be at full flaps and under 2000' or so.
17. The annunciator on the PFD should display both LOC and G/S in green at this point meaning that you've been picked up on both localizer and now the glidescope.
18. ATC will say "cleared to land runway xyz".
19. airliner should glide down to the runway. Once you hear the automated voice "retard, retard.." Pull way back on the throttle, bringing it down to "idle". Gear hits ground, nose gear hits ground. Press & hold F2 to turn on reversers

So that's my rendition of what has generally worked until now. It seems somewhere between steps 13 & 14 is when I start to notice the plane is not quite lined up with the runway - KSFO's runway. strange. Not sure what may be going on...