>>13154823iirc its post adjustment price compared to the amount the coin went down (or up) by, so if for example rushia is $12000 before adjustment and $5000 post adjustment then the difference of the two, being 7000, is compared to post adjustment price of 5000 and thanks to some math you end up with 140% decrease in price
(7000 / 5000) * 100i hope this explains it well (it doesnt)