There is a known issue currently with the sort order set on the standard values for the “/sitecore/templates/System/Templates/Template section” template and not being picked correctly and always treated as zero until you set the sort order specifically for the section thus overriding the standard value.

This has impact on section inheritance, producing unexpected behavior in the following case:
1. You have an abstract “base product” template with the following sections:
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  1. You have a derivative template “monitor” with its own domain specific data section:
    image

  2. You want to have certain sections from the “base product” template show up first, then the “data” section from the “monitor” template itself, then the rest of sections from base:
     

Since the default inherited sort order for a section is 100 (coming from __Standard values), however you won’t be able to accomplish this by setting the sort order of “descriptors” and “product data” section to 80 and 90 correspondingly.
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There is an easy and simple way to solve this by simply setting the sort order of “descriptors” and “product data” sections to negative values (-2 and -1) for example.

Enjoy!