Did you take into account that, out of approximately 7K candidates between 400-450, most of them have already been flushed out in the last draw until 423? this leaves approximately 5.7K candidates between 400-450. Keeping the factor of 1K newcomers in this segment, that leaves around 7K candidates in this segment. With a draw of 3.6K let's say, the score should drop to 413 right away.
Same thing happened with the 415 draw.. everyone above 415 was flushed too!!
The rate of ppl applying with +415 seems to be really high.