If I own a 5D II with a shutter count of 1000 and a 5D III with a shutter count of 8000, then I put my card from 5D III in 5D II and take a picture, the file number will be 8001. Then I sell 5D II to you. You format a card and take a picture that will be nr 8002 but the shutter count is just 1002.
The shutter count bug I am talking about is something difference and as I wrote, will not happen before 2048. When you reach 2048 you can try it. Take 10 pictures, remove the battery and check the shutter count after that. 5D II stores the shutter count in RAM before saving it to eeprom. After 256 pictures it will save from RAM to eeprom. It means that if you have a count of 2048 and take 255 pictures and remove the battery you will still have a shutter count of 2048.
