As you can read on the coinpage, the difference is in the last group of heraldic flowers. The problem is, it's not always very clear. It's very clear though when the three groups are complete (the pictures with a green circle):

These are old coins, with often wear, so it's not always obvious if the last group is complete or not (the pictures with a red circle):

But I've finally found one where you can clearly see the last group is not complete:
