Surely the date error would go the other way? If the Americans are in Hawaii and it's (say) 1 February, in the landing zone in China it would be 2 February, no

Surely the date error would go the other way? If the Americans are in Hawaii and it's (say) 1 February, in the landing zone in China it would be 2 February, not 31 January. So if a mistake were made and they had said "the attack is on 1 Feb, be prepared", the Chinese strips would be ready too early, wondering where the Americans were, and then do a little math to figure out they'd be needed the next day instead. Right?