Different Disks, Problem or Glitch?

[condorz38]

Had a problem with my disk (open tray, close tray, reading, open tray) so I went to gamestop and they found a little piece missing next to the large hole, only visible when you hold it up to the light. I traded it in for another new BOP (cost after trade and customer discount $20 and change). Anyway, I got home and played, everything works great, except for something odd I noticed this morning in strike. I have played a lot of ranked strike in arcade mode. Today same map, same plane, same bomb load as before (B-17, 2000 lb bombs, ardennes map). Before trade, I could destroy all targets and take all tickets off, score 32 if no planes shot down by me. Today, same mission, no planes shot down by me, score 36. Tried it many times, always the same result, score 36; which means new disk is showing 18 targets and not 16. This causes me to wonder if there are other disparities between disks. Both look exactly the same, but if there is a difference in strike between them, is there a difference in other modes and difficulties? While the possibilities are endless in combination, could a different disk make the other modes and difficulties easier or harder because of the disk you have? Maybe top speed and accuracy are also different, which would skew results for those who have a better disk. Has anyone else noticed this? Or have an explanation of the differences in disks?