Interestingly, if you read the Twitter feed, there is a question raised about a post by Honigstein on May 11th which states that Arsenal were going to pay the full amount (https://twitter.com/honigstein/status/733286121703149568?ref_src=twsrc^tfw). I suspect that there is a fair amount of "playacting" going on.
Is it a question of Xhaka or Kante, but not both? All we can be assured of is that we will never know exactly what goes on behind the scenes.