for_M_total <- pred_M_hi_xts + pred_M_lo_xts

M_t_v <- bev_xts_valid[,"M.hi"] + bev_xts_valid[,"M.lo"]

MAPE <- 100*mean(abs((for_M_total - M_t_v)/M_t_v))
print(MAPE)

[1] 7.599677