When entering wear measurements, depending on how the software is configured for your site, you may see a column in the results grid for Y values. Y values are designed (see here) to allow users to record wear measurements taken at more than one location along a belt section.
If measurements are only taken at one location, the web software and the iPad app both now default to a Y value of 1. This shouldn't be deleted or changed unless there are tests taken from more than one location.