The high school physics:
Single piston calipers have a piston diameter of 66mm = 5.30 in^2 for fluid to press against.
Rotors for aforementioned calipers are 10.87in diameter or 5.44 in radius
Braking force = distance * area * pressure (5.44 in * 5.30in^2 * 1 lb/in^2)
So, for every lb pressure of brake fluid acting on caliper piston, you get 28.8 in. lbs. of braking force on the rotor
Dual piston calipers have a piston diameter of 46mm = 2.58 in^2 for fluid to press against, but there are 2, so total area 5.15in^2 (note slightly less than the single pistons).
But because the single pistons are 20mm smaller in diameter (10mm/0.39in radius), engineers could make slightly larger rotors without caliper coming in contact with the rim - 11.26in diameter or 5.63 in radius
Braking force = distance * area * pressure (5.63 in * 5.15in^2 * 1 lb/in^2)
So, for every lb pressure of brake fluid acting on caliper piston, you get 29.0 in. lbs. of braking force on the rotor
For all intents, identical. (Ford could have actually went all the way to 11.66in diameter rotors with dual pistons had they felt the need)
Note: Pad area is irrelevant - At least for high level discussion.
There are some subtle advantages of spreading force over length of pad versus centralized, but that gets into complex calculations, beyond this forum.