Apart from 4atb gives you and extra person in midfield, which is why we can get over run, keeps full backs back slightly so Manning wont get caught up field like he does, releases Fellows into his favoured position, 'should' be better communication from 2 cbs between themselves for who goes/drops/picks up unless we go zonal. Less space in behind to put in all these crosses and gives you options of 433, 4231 4141 all whilst trying to build a somewhat as best we can cb pairing which granted is difficult