Hi Mario,
In that bill it says the following;
(a) SALE PRICE.—The coins issued under this Act
shall be sold by the Secretary at a price equal to the sum
of—
(1) the face value of the coins; and

(2) the cost of designing and issuing the coins
(including labor, materials, dies, use of machinery,
overhead expenses, marketing, and shipping.

This would mean $1+design cost+material(approx $26/oz)+die cost+production+overhead+marketing+shipping=approx $30-35 today.

I would think that the material cost is how much it costs to get 26.73 grams of silver.
That's the way I see it.