It is very important to write the number of the loose sheet because if the book is not sewn , if for some reason the seam is opened and the loose sheet is disconnected , if the loose sheet is torn due to transportation , sending to teaser, etc., then the book is matched by looking at this number. You can't blame the authorities for not having the result of such an accident in the unwritten book. That is the importance. Now if none of the above happens , there is no problem if the loose sheet is properly attached to the account. The result will come. The register will be evaluated. But if you fail according to the quality of writing, it is a different matter.