Just to put this theory to rest.
Hughes scores in Shield games away from Adelaide oval: 95 & 83 (vs Qld), 158 & 8 (vs Vic), 92 & 26 (vs WA), 86 & 16 (vs Sri Lanka in Hobart), 5 & 1* (vs S. Africa in Sydney for Australia A)
Hughes scores in Shield games at Adelaide oval: 3 & 37 (vs Tas), 8 & 8 (vs Qld).
Don't you dare include the game against Sri Lanka as a Shield game... Sri Lanka are no where near that standard.