Wanted : Actual or self confessed Chipco experts to answer this question.

Why would the same type of sample have a different amount of notches? I would have thought that samples were made at the same time & therefore notched at the same time using the same tool or machine & the same amount of times. Can anyone shed any light on the process or why they would possibly make the same sample at different times? Also, has anyone else seen this on chipco backed samples before? Thanks

Cheers, Tim.