So they increase margin to cover for uncertainty and incorrect estimations. And in case the original estimations were right, the higher profit is just unintended consequence.
Since it's not market optimal, after they note the extra profit, why don't they lower the prices or hire more workforce or expand?
Or at least share the windfall with employees indirectly boosting the economy total, including their own position?
(Yes, equilibrium economics is a joke even when law of big numbers is involved.)
(Yes, equilibrium economics is a joke even when law of big numbers is involved.)