When classifying by intervals, better try $case = int( ($ref-1) / 8 ) , so you only have to test for the results 0,1,2,3...

DB<104> for $ref (1,8,9,16,17,24,25,32) { print "$ref: ", int(($ref-1)
+/8), "\n" } 
1: 0
8: 0
9: 1
16: 1
17: 2
24: 2
25: 3
32: 3
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