Add some comment

Check.pm

@@ -102,13 +102,14 @@ sub action
         $new_size_q3       = eval { int $sizes->quantile(3) } || 0;
       }
 
-      # TOO BIG ?
+      # Using a mathematical formula to calculate the consistency of the average size, for new files, on all backups
+      # TOO BIG ? If the size is 6 times higher than usual :
       my $toobig = 0;
       if ( $new_size > ($new_size_q3 + $new_size_q3 - $new_size_q1) * 1.5 or $new_size > $new_size_avg * 6 ) {
         $toobig = 1;
       }
       
-      # TOO SMALL ?
+      # TOO SMALL ? If the size is 3 times lower than usual :
       my $toosmall = 0;
       if ( $new_size < ($new_size_q1 - $new_size_q3 - $new_size_q1) * 1.5 or $new_size < $new_size_avg / 3 ) {
         $toosmall = 1;