That's what I know based on several experiences of difference users when they received different level up rewards for the same VIP level. Those who play slots game only received higher amount than those who play the in house games such as dice or crash. It should be also confirmed with the information under the VIP lounge as quoted below:
On top of that, we now offer you dynamic level up rewards which is 12.5% of house edge!
In a simple explanation, the higher house edge of the game you play, the higher level up rewards you will get.