The value is revised to about four, with 60% to 50 pairs.
Suppose the source data is in column A, starting with A 1
Enter at B 1
=ROUND(A 1，2)-(MOD(A 1* 1000，20)=5)/ 100
Enter and fill down.
As for "explaining how this set of numbers works and why", it is necessary for statistical operation, with the aim of expanding the deviation (searching online by yourself).