Without going into the detailed complexity of it, there is a difference.
Briefly, for players under that category, it is a points system, and the biggest one is the player's wage relative to the average wage at the club to scores points. A player needs to be in the top earners percentage. Our wage average is much higher than Leicester's so he would need to be paid a lot lot more to qualify, in line with the top earners at the club. There are a few other criteria too, but that is the main one.
This is why Douglas Luiz couldn't get a work permit to play for Manchester City, but could for Aston Villa, in the same league and country. From my brief look at it early on when we were linked, it looked to me like the exact same scenario.