Irish Invader Grand National Weight

Whatever about the weight given to War of Attrition how on earth can the handicapper come up with the weights of Mon Mome and Irish Invader. In the race last yr Mon Mome gave Irish Invader 5lb and a 44l beating and now finds himself better off by 3 lb. Irish Invader admittedly ran off his old mark of 143 last yr before he was reassessed for winning a pair of 5 runner condition races at Thurles .Current rating of 148 Ir h/c mark but given 153 here. Given how uncompetitive those Thurles races were even a mark of 148 looks high enough.