Not quite...
Richard,
The house edge for your game is 0.34%, so you would have to surpass that amount to have the advantage.
On a $7.50 bet, the normal return for a BJ is $11.25, so by getting $11.50 you're receiving a "bonus" of $0.25, which in terms of your initial bet is (+$0.25/$7.50)*100% = +3.3333%.
But how often do you collect the bonus? In a 6D game, the probability that you'll get a BJ can be calculated as follows.
BJ Prob = (Prob of Ace)*(Prob of X) + (Prob of X)*(Prob of Ace)
Where "X" is any 10-valued card.
Of course, the two terms on the right-hand side of the equation are equal, so instead we say:
BJ Prob = 2*(Prob of Ace)*(Prob of X)
Since a 6D shoe contains 312 cards including 24 Aces and 96 X's, we get:
BJ Prob = 2*(24/312)*(96/311) = 0.047489..., or a bit over 4.7% of the time.
But wait, there's more! To get the bonus, you need to get a BJ without the dealer also having a BJ. The untied BJ Prob is given by
Untied BJ Prob = 2*(24/312)*(96/311)*(1-2*(23/310)*(95/309)) = 0.045322..., or a bit over 4.5% of the time.
In this equation, the term "2*(23/310)*(95/309)" is the dealer's BJ Prob given that YOU already have a BJ, so "(1-2*(23/310)*(95/309))" is the dealer's probability of NOT having a BJ given that YOU have a BJ.
So, the net effect of the Bonus is to give you a bonus of +3.3333% a bit over 4.5% of the time. Multiplying these percentages gives you a bonus of +0.15107...%, which is insufficient to overcome the house edge of 0.34%, though it does reduce it quite a bit.
Hope this helps!
Dog Hand