Believe it or not, Dozy, the conditions for 447 do not mitigate their performance. One knows, or one doesn't. DC-ATE is right. Good bad or indifferent, it shouldn't make any difference. To try to soften their foulup is a wheeze. If the conditions were sudden onset, or out of the ordinary, fine, some slack.
None is given. Eyes wide open, no room to hide. No excuses.
Stick to Computers.