oil to travel around the entire area of the crank pin between the crank and the bearing - except in this case the oil has two ways to get out of the bearing - either side. The oil will essentially be delivered all around the circumference of the crank pin itself rather than just from the two holes. Since the gap between the crank pin and the bearing is the 'restrictive' area, doing this particular mod will not affect oil pressure at all. It simply distributes the oil flow all around the pin rather than just at the holes.