Our business has some specific ways of handling Cases/Trouble tickets and classify them according to several levels,  e.g. Financial->Bill-related->Usage->Overcharge.  They also have a measure called 'Severity' which is related, but not a 1:1 mapping with Priority.

Our SI has just extended the data model to hold all of the above rather than using the OOTB fields in Pega to define the type and priority of the Case.

Is this a good approach? It seems to require a lot of effort and customization, so I am concerned that we are going down the wrong path. Any comments from others who have gone through this?