Double Down on Soft 19 and 20

In the instance of having a A/8 in a 6 deck shoe (S17) the win
probabilities are:

52.1 against a dealers 2, 53.7 against a 3, 55.1 against a 4, 56.7
against a 5, 58.6 against a 6, 54.3 against a 7, 50.5 against an 8.

The loss rate is 40.0, 38.6, 37.4, 36.1, 34.5, 38.3, 40.8 respectively.

It's even better for A/9:

Win rate for 2-8 for the dealer is, 55.1, 56.4, 57.8, 59.4, 60.9,
55.9, 53.3 repectively.

With a loss rate of 37.0, 36.0, 34.8, 33.6, 32.3, 36.6, 38.4 respectively.

If the math is correct, why not double down as you would on hard
10's and 11's?

Isn't the objective to press the advantage and get more money out there?