Similar to the Fm21 4-4-2: the inverted wing backs underlap to provide a transition to the midfield whilst the wingers overlap to create width. The Mezzala's swoop in to advanced midfield positions on the attack overwhelming the defense. In the original 4-4-2@mezzala, the inverted wing-backs plugged the whole in the middle during transition from loosing possession, at least 90% of the time, however this depends on how good your wing backs are. Since my wing backs are poor, I found the original formation was leaky and gave me poor possession. Advancing one of the central defenders to halfback position provides more opportunities to shore up loose balls following an attack.