The top level is 27. After getting level 27 you get no message about getting more experience points, though you can see the bar gping up. But once you've got those 126189 points it stays like that, no matter what you do ...
I don't know if it is better or not to what happens with the influence points: once you reach level 20 you don't get the message about getting more influence but you can see the bar going up and up, now I have 54,145 and only 20,000 are "required" to reach the next level, i.e. I have an excess of 34,145 influence points
That makes me think that the extra influence points are not lost and that if the level cap is removed I could get 2 or 3 inquisition perks at once. But I am afraid I am losing all the extra experience points as they are not shown on screen 