Afaik the calculation for the leveling up reward is fixed (12.5% of the house edge), but the amount you receive may different depends on the house edge of the game you play. Lets say you wager $500,000 on games with lower house edge (blackjack or crash), you will get lower amount compared to what is received by roycilik as I believe all his wagered amount is on slot games with higher house edge than blackjack and crash.