Yeah, going from 18.80 to 34.47 would be an 83% increase. But going from 34.47 to 18.80 is a 45% decrease. As to your question about whether this is some sort

Yeah, going from 18.80 to 34.47 would be an 83% increase. But going from 34.47 to 18.80 is a 45% decrease. As to your question about whether this is some sort of acceptable alternative way to calculate percentage decrease ... no, this is just a math error.