while (<DATA>) {
  /# input for/ .. s/1\.00/5/g;
  print;
}
__DATA__
# input for Data

1.00  0.99  0.92
1.00 -0.22  0.61


##</code><code>##

use strict;
use warnings;
while (<DATA>) {
  if (/# input for/ .. /\d/) { s/1\.00/5/g }
  print;
}
__DATA__
# input for Data

1.00  0.99  0.92
1.00 -0.22  0.61