The subject code of my paper is not the one I submitted, why is it different?

 
The subject code of my paper is not the one I submitted, why is it different?
 
Occasionally an author assigns a subject code which we feel does not reflect the content of the paper. In these instances, our editorial staff makes an informed decision taking into account the content of the paper and assigns it a new primary subject code. Additionally, some codes are frequently misused, such as confusing Mathematics Education (Humanities, Education) with Mathematics (Sciences, Pure Science).