The last 2 spots on the VIP arena were changed. Now Deep dungeon hell spider and Deep dungeon Gorgon are there. But don't worry, experience, gained from them, will be more, than on previous spots.
Yes, got more xp but the respawn time is almost 15 seconds compared to lower mobs where respawn time is 5 seconds. Are you fooling us?????? or you never tested it?
Ultimately, you got more xp per time elapse.