This is a great rule! Only losing one-third of your $3 bet by surrendering adds 2.25% to your expected return. You didn’t tell me the other rules but if we assume a house edge of 0.5% before the surrender rule then the player edge afterward would be 1.75%. Here are the hands you should surrender on based on a six deck game (hit or stand on soft 17 doesn’t matter). Player 6 against 10. Player 12 or 13 against dealer 9, 10, ace. Player 14 or 17 against dealer 8, 9, 10, or ace. Player 15 or 16 against dealer 7, 8, 9, 10, or ace. The only hand you would normally split that favors surrendering is 8,8 against a 10. This advice only holds true for a $3 bet. The value of surrendering diminishes as the odd-numbered bet gets higher.