$ cat tst.awk
BEGIN { OFS="\t" }
NR==1 { next }
NR==2 { maxVal = $2 }
NR==FNR {
if ($2 >= maxVal) {
maxSth = $1
maxVal = $2
}
next
}
{ print (FNR>1 ? ($1 - maxSth) : $1), $2 }
$ awk -f tst.awk file file
[s] [K]
-5 900
-4 100
-3 200
2 1000
-5 80
49 12
0 90000
-1 1