Late surrender 17 vs. dealer Ace

[tedloc]

On your Basic Strategy chart you recommend Surrendering 17 vs. dealer Ace. I play on a 6 deck, dealer hit soft 17, late surrender game. According to your dealer probability charts the dealer will bust 20% of the time. If I make 100/$10 bets, I will get bact $500. If I use your dealer probability chart I will win 20 hands when dealer busts/push on 8 hands/lose on 70. According to my math, there is no edge either way. What did I do wrong?