You need to try again <insert serious smiley here>.
I said in my hypotherical engines that "even though the stroke and displacement are identical", this implies that the total piston area is also identical. What has changed is the number of cylinders and the piston radius) to keep displacement (and total piston area) even.
The single cylinder with the same displacement/stroke has roughly 1/3 less contact with the cylinder wall than the 2 cylinder.
The stroke is the same in both cases, the 1cyl has a piston radius of 1.414 and the 2cyl has a piston radius of 1. The total circumference (the part that rubs against the cylinder wall) is much larger in the 2 cylinder.