YoYo 21 Betting Area (click to enlarge)

Yo-Yo 21 is special in that it allows a player to increase or decrease their wager after seeing their first card. The casino charges a fee for this privilege and carries a house edge of 3%.

The casino can allow for higher limits by allowing a mixture of bets from the posted allowable bets. Example: a player could bet $150 since $50 and $100 are allowable bets on the chart. The fee to decrease would be $15 and the fee to increase would be $22.50.
This game gives the player a feeling that they have some control over the outcome. We know this is not the case but why spoil it for the customer.